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Blossoms and Brimstone

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The first time he meets his Sensei, it’s raining.

Genya is a few months shy of thirteen and just a little bit terrified. Sanemi had been gone for just a few years when Genya had overheard a conversation between two men passing through town. Those men, it turned out, were a pair of Tsuchinoto who had just gotten word about the appointment of a new Wind Pillar to the Demon Slayer Corps; a violent, foul mouthed young man with snowy hair and scars decorating his face. Genya had immediately sought out the Corps and tried to find a trainer of his own, but it had quickly become apparent that he couldn’t perform even the basics of a breathing technique, let alone master one. In his desperate frustration he’d resorted to something all together rash (he can still feel the resistance of raw, flexing muscle under his teeth, taste the salt and metal of blood on his tongue) and ended up at the Butterfly Estate waiting for, what he thought, would be his sentencing.

Which is why he’s so surprised when the Flower Pillar’s younger sister, Shinobu, comes to fetch him.

She’s silent as she leads him through the quiet halls of the Estate, but he can almost feel the disapproval radiating off her.

It’s as they approach the front door that voices reach them. Turning the corner, they can see Kanae speaking with someone who’s just come through the door. Water drips from the wide brimmed hat, darkening the shoulders of the coat they're wearing, falling to the floor even as they reach up to pull the hat away.

“How was your trip, Reimei-san?” Kanae asks, accepting the hat from the woman standing in her foyer.

“Well enough, thank you, Kanae-san.” The woman, Reimei, responds, but Genya doesn’t hear any other part of their conversation because he is completely transfixed.

Reimei is a little taller than Kanae, putting her about half a head taller than him. She’s only a few years older than him, too, probably around the same age as his brother, but the lithe, easy grace with which she moves speaks of an accomplished, seasoned warrior.

But what fascinates him the most is the fact that her hair is a bright, vivid red, like the petals of a camellia. Pulled into a bun at the nape of her neck and partially covered with a kerchief, it’s still eye catching enough to be the first thing he notices. The second are her eyes, grass green and suddenly fixed on him curiously.

“Are you Genya-kun?” She asks, stepping up onto the hardwood floors now that she’s shed her muddy shoes and wet coat, revealing a standard Corps uniform covered by a green and white yagasuri patterned haori. He nods dumbly, staring up at her in awe. He’s never seen such coloring on a person before and he’s embarrassed at his own fascination. She smiles at him, gentle and warm, before offering him a small bow.

“My name is Reimei. I hope we get along.”

He soon finds out that Reimei is a Kinoe ranked member of the Corps, second in strength only to the Pillars, and his newly assigned Sensei. He’s surprised, so sure had he been that no one was going to take on someone who would eat demons to assume some of their traits. Learning that Ubuyashiki-sama had specifically assigned Reimei to him had confused him even more, but that confusion had turned to understanding in less than a week.

They leave the Butterfly Estate the day after Reimei arrives, heading towards Kyoto at a leisurely enough pace. Reimei doesn’t seem to be in any particular hurry, stopping every now and then to show him a new technique he can try. Most of them are simple kata and physical exercises to increase his stamina, and he practices them whenever they stop.

Four days later sees them on the outskirts of Kyoto, dropping off their scant belongings at a rather nondescript looking inn. Until, that is, Reimei quietly points out the family crest hanging by the front door, surrounded by Wisteria flowers.

After that they start their patrol, Genya trailing after Reimei through the heart of the city, slightly uncertain but determined even as the afternoon darkens into evening. They wander for some time, watching the population of the city flow through the streets like a river. They don't stop again until close to midnight when his stomach makes itself known, growling loudly in the quiet.

Reimei tilts her head, gentle smile never wavering even as Genya ducks his head, utterly mortified.

“How does udon sound?” She asks him, startling him out of his embarrassment.

“Y-yes please, Sensei.” He mumbles under his breath.

They head back towards the more residential part of the city, settling on a little stall just off of one of the main boulevards. Reimei orders two bowls for him with extra tempura and one with an egg for herself.

“As my student, it's my responsibility to take care of you. And growing boys need more food.” She explains at his confused expression.

“But Sensei, you’re only a few years older than me.” He points out and she laughs, the sound bright and clear in the quiet night.

“Maybe, but I’m not really expecting to get any taller. Dig in.”

It’s as he’s starting on his second bowl that he feels Reimei go completely still at his side.

“Sensei?” His voice is only slightly muffled by the food he's actively shoveling into his mouth, but she isn’t looking at him, instead staring off into the darkness unblinkingly, eyes eerily bright.

“Please stay here, Genya-kun. I’ll be gone no longer than an hour. Stay in the light.” She says, setting her bowl aside and standing smoothly from her seat.

“But...Reimei-san?!” But she’s already gone, disappeared like just another shadow into the dark, leaving Genya stunned speechless.

Glancing to the side he can see that she’s barely touched her own bowl, having only picked lightly at the noodles.

One minute turns into ten, then twenty, and Genya’s worry only mounts. Finally, with a fearful gulp, he grips the training blade he’d been given when he first started trying to learn breathing techniques and sets out into the night.

He doesn’t have anything to go on, only his poor senses that only marginally improve when he tries to dreg up the last scraps of the first demon he’d eaten. Even with slightly better than average night vision he still stumbles through seemingly abandoned streets for a solid fifteen minutes before he hears it.

It starts as a low growling, the reverberation picking up strength as he follows the sound until he can feel the thump of it in his throat. It nearly makes his eyes water, but he doesn’t stop, his worry for his new Sensei only increasing.

He’s just turned into another empty street when the growling suddenly changes into a horrible, ear splitting shriek that splits through both the night and his eardrums loud enough to make him wince. He stumbles, fear making him shake, but he forces himself to breaks into a run, reaching the next corner as the shriek is petering out, turning to a pitiful whimpering before falling silent entirely just as he rounds the bend.

Genya skids to a stop and freezes, his breath feeling like a lead weight in his chest as the sight before him comes into focus.

Halfway down the alley a streetlight illuminates a slumped figure, limbs akimbo where they'd collapsed against the nearest wall, not quite glassy eyes scrunched in agony. The body shudders, jerking unnaturally each time the person crouched over them rips deeper into their insides. A terrible crunching reaches Genya’s ears, the sound of bones being snapped like toothpicks under uncaring hands as layers of skin and fat and flesh are peeled back, revealing the still beating heart. The body twitches only once as the organ is ripped free, finally starting to crumble as teeth set into tender muscle.

It only takes a few moments for the heart to be consumed, but to Genya it feels like an eternity because all he can see is red.

The red of blood staining the pavement.

The red of sharpened, dripping claws.

The red of the harvest moon hung heavy and fat in the sky above them.

The red of his Sensei’s hair and eyes as she straightens from her crouch, wiping at her mouth with the back of a hand, smearing blood across her lips and chin. The crimson of her sclera makes the green of her irises even brighter, more unnatural, sharper as they cut to him. The sound of her footsteps is oddly loud, echoing in his ears as she approaches.

Genya has no idea when his legs collapsed out from underneath him, but he only fully realizes it when Reimei has stopped in front of him, that much taller from his position on the ground.

“I told you to wait at the stall.” She says, voice a little deeper, a little bit warped. Genya tries to swallow around his paper dry throat, because knowing he’s done this, eaten a demon, is nothing like seeing it happen before his eyes.

He manages to turn away from her at the last second as he feels the burn at the back of his throat, heaving violently between great gasping breaths that do nothing to reduce the panic quickly rising in his chest. He nearly jumps when a cool, dry hand touches the back of his neck, fingers brushing through his hair in a soothing gesture.

“Easy. Try and take deep, even breaths.” At Reimei’s soft voice he shudders, eyes squeezing closed as he tries to slow his wildly beating heart and bring his erratic breathing under control.

Long minutes later he can take normal breaths again and he feels a gourd being pushed into his hands.

The water is cold and crisp and he spits out the first mouthful to rinse away the taste of bile before downing the rest.

Finally, he glances uneasily at his teacher, finding her eyes once more back to normal. They’re fixed on him, a hint of sadness visible in their depths.

“I apologize, Genya-kun. This is not how I wished for this to go.” She says. Slowly, she pushes herself to her feet and offers him her hand. There are faint traces of blood left under her nails and smudged along her jaw, but the majority of it has been wiped away.

“If you would like, we can go back to the inn and I can explain. Or I can call the Master and have you reassigned.” She offers. Genya blinks up at her, uncertain.

“Explain what, exactly?” He manages to ask, his voice hoarse. Reimei tilts her head a little.

“Me.” She responds, gesturing briefly to herself.

He hesitates another moment before, slowly, reaching out to take her hand.

Genya doesn’t get much sleep that night, lying awake for hours thinking about what his Sensei had told him.

After they'd gotten back to the inn she’d sat down across from him in their shared room, poured tea for the both of them, and then fixed him with her sharp green eyes.

“I hope you understand, Genya-kun, that what I am about to tell you must never leave this room.” She said. He swallowed thickly, but nodded, determined. Reimei had watched him for another moment before letting out a deep sigh.

“The two of us share a unique ability; we can consume demons without adverse side effects. Though I imagine the origins and reasons for such are a little different.”

“Origins?” He couldn’t help but ask, and for just a moment her eyes flicker, an unbearable sadness reflected in their depths.

“The circumstances of my birth are...complicated. However, because of that I stand on the border between humans and demons.” Here she held up her left hand, palm up.

“You are fully human, Genya-kun. You sustain yourself with regular food and water, and only consume demons in order to enhance your natural strength.” She holds up her other hand to mimic the first.

“Demons, despite once being human, can only sustain themselves by devouring humans. They also give up their ability to walk in the sun for enhanced speed, strength, and healing abilities, as well as an unnaturally long lifespan.” She brought her hands together, like she was cupping water in her palms.

“I stand somewhere in the middle. While I can survive mostly on human food, there are times when I must feed on demons. And I do not do it to enhance my strength, but to survive.” She let her hands fall to pick up her tea cup, taking a slow sip before continuing.

“Despite all of that, I am not a demon. I can walk in the sun and nichiren blades do not affect me any more than normal ones. However, I am not entirely human, either. My regeneration speed, for example, while not instant, is much faster than a normal persons.” Here, she extended her left arm and pulled up her sleeve, revealing a set of three jagged claw marks on her forearm that stand out starkly against her porcelain skin.

“The demon I ate earlier this evening did this to me. As you can see, it is already scabbing over. By tomorrow morning it will most likely be gone entirely.” She said.

Genya couldn’t help but stare, transfixed. The wounds indeed looked several days old instead of their actual age of barely an hour and he felt a kind of morbid fascination at the sight of them.

“I was assigned as your teacher because you can do something similar. By consuming demons, you will gain not just their strength, but their regenerative abilities, as well. Depending on the demons you eat, you may even be able to go head to head with a lower moon by yourself.” She explained.

“People like you, Genya-kun, are actually quite rare. Even rarer than marechi. You see, though all humans possess the ability to do so, consuming the flesh of a demon usually has only two results. Either the human in question crumbles away when the demon's power runs out, or they go mad with the demon’s blood and start attacking other people.”

“They turn into demons?” Genya asked, horrified. Reimei shook her head.

“No, they become something much worse. They lose all of their cognizance, devolving into little more than wild beasts that attack anyone and everything indiscriminately. But, unlike real demons, they gain nothing from eating humans. Sometimes, they are caught by human authorities and executed, but more often than not their madness drives them to start eating their own bodies, killing them in the process.”

Genya swallowed thickly, horror making his chest tighten.

“As you might think, my own circumstances notwithstanding, for this reason eating demons is strictly forbidden by the Demon Slayer Corps. And almost all information on consuming demons is kept a closely guarded secret, hidden behind as many layers of taboo and regulation as Ubuyashiki-sama can manage. My own movements, while not restricted, are also kept under wraps. To most, I am simply a particularly efficient Kinoe who dislikes company. Ubuyashiki-sama and Kanae-san are the only two who know of my true nature, partly to keep me safe from other members of the Corps, but mostly to prevent this information from reaching Muzan.”

They had fallen into silence as Genya had processed everything Reimei had told him, mulling over the implications quietly until something occurred to him.

“Won’t you get in trouble for telling me all this?” He asked, curious. Reimei shrugged.

“Maybe, but I told you, as my student it is my responsibility to take care of you. This is information you need, so I’ll deal with the consequences when I come to them.” She explained. Genya had blinked, feeling his chest tighten at the conviction in her tone.

Now, Genya stares into the still darkness of their room, listening to his Sensei’s soft, even breathing, and feels his mind finally settle.

It’s odd, he thinks, how comfortable he is. Not since he was living with his mother and siblings had he felt like this, and for it to happen in such a short time is unusual for him. But there’s just something about Reimei that puts him at ease, makes him want to curl up and huddle in her shadow like a small child, so assured is he of his safety in her presence.

Even when she'd been staring him down in the alley, crimson eyed and bloody, he hadn’t been afraid of her.

Maybe it’s because he hadn’t felt any hostility from her, or because of her constant assurances that it’s her duty to look out for him, but as he finally closes his eyes and slips into a dreamless sleep, he thinks that he might have been incredibly lucky getting her as his teacher.

Chapter Text

“What do you think of this one, Genya-kun?” Reimei turns to him, holding out the oddly shaped weapon. Blinking, he squints and takes it from his teacher, hefting it in his hands to test its weight before lifting it to shoulder height, aiming along the sights.

“And you’re sure something like this can be modified for nichirin steel?” He asks, turning the gun this way and that, admiring it from every angle. An amused smile tugs at Reimei’s mouth.

“Trust me, this is far from the strangest weapon the blade smiths have modified.” She says, turning to the shop owner to pay for their purchase. Genya can’t help but glance quickly at the racks of shiny, naked blades set along the wall, a flash of envy curling in his gut, but he eventually tucks the now neatly wrapped gun into his pack and follows Reimei wordlessly out onto the street.

At first, Genya had thought they would only travel for a little while before returning to the Corps headquarters, but it had quickly become apparent that Reimei spent a majority of her time on the road. In fact, they’ve been traveling ever since she picked him up from the Butterfly Estate. 

It had been a difficult adjustment at first, but every moment Genya spends awake is one that Reimei takes advantage of. There’s an awful lot of running involved, often with weights, and he actively dreads when they stop for longer than a week because it means that his teacher has cooked up some new hell of a training regimen.

But he’s also starting to notice the changes. He might not be up to taking on a demon himself yet (because instinctively sensing an oncoming attack is completely different from successfully dodging it) but he’s definitely getting faster and stronger.

His newest acquisition is the result of a long conversation between them where they'd discussed his weaknesses and how to compensate for them. It had been Reimei who had suggested a weapon with a longer range, and Genya had tentatively agreed.

He just hopes he can master it and that he doesn’t end up disappointing his Sensei like he did his brother.

The pill is small, innocuous enough except for the fact that it is blood red. There are maybe a dozen paper packets in the little box Reimei had untied from the back of the crow that had landed on their windowsill, handing the whole thing to Genya with little ceremony.

“They’re what?” He asks, staring down at the tiny red disk resting innocently in his palm like it’s going to bite him. Reimei reaches into her bag and extracts her own box, though the packet she pulls out holds a much, much larger version of his pill.

“They’re made primarily with demon blood. Kanae-san produces them for me in the event that I can’t go hunting or need an emergency boost. I asked her to make a smaller version for you to start getting your body used to the changes that will come with eating demons, that way you won’t be totally overwhelmed in the heat of the moment.” She explains.

Genya swallows and glances between the pill and his teacher. Reimei smiles gently at him.

“They’re micro-doses, Genya-kun. You won’t start noticing significant changes until you move to larger pills.” She assures him.

Genya drops his eyes back to the pill, barely larger than a grain of rice, and takes a fortifying breath. Without another thought, he tosses the thing back, swallowing quickly to prevent it from touching his tongue.

Nothing happens except for a faint, brief tingling sensation at the back of his throat, but the proud smile that spreads across Reimei’s face is enough to warm his insides.

Genya runs a hand impatiently through the hair at the back of his head, trying unsuccessfully to twist his neck enough to see the spots he needs to trim in the mirror. He’s not having much luck, and is almost about to resign himself to an uneven haircut when the door slides open.

Reimei appears, freshly pink from the bath and wearing a yukata provided by the inn, her still damp hair pulled back in a loose braid. She blinks sleepily at him, looking particularly relaxed, and then seems to notice what he’s doing.

“Need a hand?” She asks, moving to kneel at his side. He looks from her to the snips in his hand before relinquishing them with a resigned sigh. She must notice his frustration because she tilts her head.

“What’s wrong?” She asks him, fingers running gently through his hair as she starts to work, holding up sections to compare lengths and then making the appropriate cuts.

“I should be able to do this by myself.” He mutters half-heartedly under his breath, even as the tail end of his words turns into an involuntary whine as Reimei scratches lightly at his scalp.

“There’s no shame in asking for help, Genya-kun.” She tells him sagely. He hums, the tension quickly bleeding from his shoulders at her ministrations, his eyes sliding closed almost against his will.

A while later and Genya is nearly asleep, distantly noticing that the quiet snip of the shears had long since ceased and Reimei is now running both of her hands through his hair soothingly, his head having fallen onto her shoulder sometime during the whole ordeal.

For some reason, Genya can’t bring himself to move from that spot.

For a long time Genya has the vague idea that his teacher is stronger than most, but it isn’t until nearly a year after he becomes her student that he gets concrete evidence of such. It’s also when he realizes that the demons Reimei is being sent after, while not members of the kizuki, aren’t small fry by any stretch of the imagination.

It’s the first time she allows him to come with her on a hunt, making him promise to stay behind her, his gun loaded and his practice sword at the ready. The demon in question has already eaten over twenty people and Genya can tell that his Sensei is hungry.

It’s a vicious, drawn out, bloody affair, the demon armed with half a dozen extra mouths scattered across his body, and Genya is sure he’s going to have nightmares about snapping, snarling jaws lined with too many teeth for weeks afterwards. 

Eventually, however, they’d gotten the upper hand, Genya distracting the demon with a well placed shot right before Reimei plunged her fist through the demon’s chest, ripping out his still beating heart and tearing into it with no small amount of vindictive glee.

After, they’d made their way back to the inn, but there’s still too much red in Reimei’s eyes; her teeth are still too long, her nails too sharp, and she seems to nearly vibrate with nervous energy. She reminds Genya very much of a skittish animal, tensed and ready to bolt at a moments notice.

But Sanemi isn't the only stubborn one in the Shinazugawa family and Genya will not be deterred.

After getting a bowl of warm water and a cloth from the night hostess, he plops down beside his Sensei on the tatami of their room and takes her injured arm in hand. He carefully cleans her skin, wiping the blood from the creases of her fingers before moving the cloth up her wrist to where the demon had gotten in a nasty bite, the puncture wounds dark against her skin. He carefully dabs around the wounds, despite the fact that they’ve already closed and are scabbing over. Next he peels back the collar of her uniform to reveal a slash on the left side of her neck, also scabbed over, but he takes the time to clean the area nonetheless.

Then, wounds checked and feeling emboldened, Genya picks up a comb and reaches for the bun at the nape of Reimei’s neck.

It’s not the first time he’s done this, but her shoulders still go high and tight for a moment as he gently shakes out her hair, a crimson curtain down her back that he carefully starts to section, starting from the bottom and moving up just like he used to do for his younger sisters, ever mindful not to snag the comb in any tangles. They sit in complete silence as he works, but he is happy to note that her shoulders start to sag. The tension is slow to leave her but he works diligently, combing out her hair until it runs like silk through his fingers and then plaiting it neatly into a tail.

Finally finished, he fixes his work in place with a ribbon, but before he can draw away Reimei catches his hands with her own. When she turns to him her eyes are their usual vibrant green, no trace of red left, but there’s a crease between her brows that he’s unused to.

“You’re alright?” She asks him, voice low and hoarse. He manages a slightly strained, if genuine smile, squeezing her hands gently. He can still see the demon's twisted, snarling face behind his eyelids, but thanks to his teacher's quick movements he remains physically unharmed.

“I’m okay.” He assures her. The last of the tension leaves her shoulders and she slumps forward slightly, her forehead coming down to rest on his shoulder.

“I’m glad.” She says softly, almost quiet enough that, if she hadn’t spoken directly in his ear, Genya might not have picked it up.

He feels his heart swell and leans his head against hers, taking simple comfort in knowing that they’re both alive.

They'll deal with the nightmares later.

Genya is almost fifteen when Reimei gives him an interesting choice.

They’re passing through Morioka on their way down South in preparation for winter, the weather already having started to get noticably colder. They’re eating dinner from a yakitori stall and watching the late afternoon bustle of the city when Reimei turns to him.

“Genya-kun, when would you like to take the Final Selection Exam?” She asks.

Genya blinks, not really registering what she’s said, and then promptly chokes on his skewer of grilled chicken when his brain finally catches up. He manages to chew and get the mouthful down, coughing as Reimei pats him on the back, before turning wide eyes on his teacher.

“What...what do you mean? I thought I couldn’t enter Final Selection until you okayed it?” He asks, confusion and elation and fear all mixing together in his chest, tightening it uncomfortably. She nods.

“That’s true, you can only enter if I submit your application. But, while you’ve improved immensely, Genya-kun, traveling leaves very little time for proper training. If we keep up this pace, you might be able to take Final Selection in three years or so.” She taps one of her empty skewers against the rim of her teacup thoughtfully and hums.

“But, if we were in one place, we could devote all of our time to your training.” She says. Genya clears his throat, looking down at his half-eaten food. He feels slightly queasy, but forces himself to pick up another skewer.

“If we took that option, if we stayed in one place, how long would it take before I could enter Final Selection?” He asks, both dreading and looking forward to his Sensei’s answer.

“It depends. But most likely less than a year.” She replies.

Genya chews slowly, mulling it over.

They don’t speak again until they’ve both finished eating. It’s fully dark now, the crowds of the afternoon thinned to only a few people wandering the streets by lamplight.

Genya takes a deep, fortifying breath before turning to face his teacher.

Mount Kita’s bare peak is visible through the trees long after they enter the forest at its base, looming overhead like an ominous, hulking bird, wings outstretched to either side to create the jagged line of the summit.

Halfway up the mountain, a good half mile past where the dirt road ends, is a small house, hidden so well among the trees that Genya doesn’t even know it’s there until they’re practically on top of it.

He can’t help but stare as they step out into the clearing, leaning against a tree as he briefly catches his breath.

The house obviously hasn’t been inhabited for several years; the garden is overgrown, the roof is in need of re-thatching, and the door is locked by way of several rusty nails driven into it along the frame, which Reimei has already set about removing.

When she finally pulls the door open it squeals loudly as it slides along the track, making Genya’s teeth grind. Inside is dusty, but there’s evidence that this was once someone’s home; a chest of drawers set against one wall, a stack of pots and pans left by the hearth. The methodical way with which things have been covered, everything carefully tucked away where it belongs, suggests that whoever lived here did not leave in a hurry.

They spend several hours cleaning and airing the place out, time that Genya spends developing a theory. When they’ve finally hung up the last of the bedding to air and have put away their things, he turns to Reimei.

“Sensei, was this your house?” He asks tentatively.

He doesn’t really need or expect a verbal confirmation. It’s there in the softness of her eyes, the familiarity with which she moves around the space. It's evidenced by books and journals that he'd found on a shelf that bear familiar handwriting, the fact that there are clothes here, in her size, that would be appropriate for an unmarried teenage girl.

She turns to him from where she’s setting up a fire in the hearth, the glow of the smoldering coals casting shadows across her face. They’re not enough to disguise the sadness in her eyes, however.

“It was.” She says, voice soft, and Genya feels his heart clench in sympathy.

Suddenly, standing in this small house, the smell of dust still hanging in the air, he knows without a shadow of a doubt that he and his teacher share the same type of grief, the same kind of loss. There is a deep seated sadness in her voice, the curve of her shoulders, the set of her mouth, that tell of a raw wound that he knows will never truly close.

He moves to sit beside her as she starts to prepare their supper, quietly supportive, and silence reigns over them as they eat and then finish up their chores. In fact, it's not until he's preparing for bed that she speaks again.

“Get some sleep, Genya-kun. Tomorrow, the real work begins.”

Chapter Text

Genya senses the wisteria trees long before he sees them. They’re a prickle at the back of his neck, an acrid taste on the tip of his tongue, a sense of foreboding that he can’t shake even as he steps under the canopy of blossom heavy branches. He swallows around his dry throat and reaches up to grip at the cloth tied around his neck, the familiar green and white yagasuri pattern a welcomed comfort.

Reimei had given it to him right before he’d left for Mount Fujikasane, worry reflected clearly in her eyes.

“I...I know that this isn’t the meaning behind the pattern, but…” She'd trailed off, mouth twisting. Despite her loss of words Genya had reached out to take the piece of fabric from her, a foot by foot square that he tied like a kerchief around his neck, because he recognized the gift for what it was.

A good luck charm.

“Remember, Genya-kun, Final Selection isn’t a competition to see who can kill the most demons. It’s a battle for survival.”

His teacher’s green eyes had flashed, unreadable and fathomless.

“All I ask is that you come back alive.”

With those words ringing in his ears, Genya steps out into the clearing to join the other Demon Slayer candidates, shoulders set, determined.

He will not fail his Sensei.

“I received word that the Final Selection Exam began yesterday afternoon.” Ubuyashiki remarks airily. Sanemi blinks, sipping at his tea silently as he mulls over that statement. It doesn’t really have anything to do with him, so he doesn’t say anything.

If he’s learned anything in his time as a Pillar, it’s that if the Master has a point, he’ll get to it when he damn well feels like it.

“Shinazugawa Genya is listed as participating.”

Sanemi is distantly aware of the sound of porcelain shattering as his teacup fractures in his grip, but he's far too distracted by the sensation of ice flooding his limbs to care, numbing his fingers as he fights for a proper lungful of air.

One breath, then two, forced in and then out as he struggles to control himself. 

But it’s proving to be difficult as the sensation of cold is suddenly replaced, burned away by white hot rage. 

“How?” He snarls, teeth gritted so tightly that they creak from the strain. Ubuyashiki’s expression remains unchanged, though there might be the slightest hint of reproach shining in his eyes.

“He was assigned a trainer over three years ago, Sanemi.” He says softly, but not even the Master’s calm tone can soothe Sanemi's rage.

It honestly feels like he’s gone a round or six with Himejima, his chest aches so badly, his vision tunneling at the very thought of his baby brother on Fujikisane, alone and surrounded by bloodthirsty demons. 

Out of his reach. 

“Who?” It’s a sibilant hiss, wheezed out from Sanemi’s tightening throat. Whoever the fuck dared to put his little brother in danger is going to regret it, and he's going to personally make them realize their mistake when he he beats them senseless with his bare fists. 

Ubuyashiki blinks his sightless eyes, head tilting forward the slightest bit as a hint of a smile curves at his lips.

“I believe the two of you have history.”

Tanjiro doesn’t even make it to the stairs, which is both incredibly sad and incredibly impressive, given the week he’s had. He’d taken the first step down, using his sword sheath as a makeshift crutch, when his leg had buckled out from under him. He fully expects to hit stone, but instead an arm loops around his middle, yanking him up and stopping his fall.

“Woah, easy.” Tanjiro twists his neck, the voice in his ear gruff but not hostile, and stares up at the older boy who had been one of the last survivors of the exam, taciturn and sullenly silent all through their ‘orientation’. His unruly yellow-tipped black hair is damp and Tanjiro wonders if he didn’t just dunk his head in the stream before starting his trek down the mountain, despite the chill in the air.

“Thank you.” Tanjiro manages, still a little breathless from the adrenaline rush of the fall. The taller boy glances at him, then back down at the steps, before he lets out a resigned sigh. The next thing Tanjiro knows, he’s being hefted up and carried down the steps.

“I...I can walk!” He squawks, taken aback, but the other boy just rolls his eyes and doesn’t respond.

At the bottom of the stairs he sets Tanjiro back on his feet, making sure he’s steady before taking a step back.

“Which way are you headed?” He asks and Tanjiro blinks, leaning heavily on his sheath.

“Mount Sagiri.” He responds and the other boy nods.

“I’m headed for Mount Kita, so I won’t be able to accompany you. Have a safe trip.” He says somewhat stiffly.

“Thank you, um…” Tanjiro trails off.

“Shinazugawa Genya.”

“Thank you, Genya-san.”

“It was no trouble. Besides, if I had let you fall my Sensei would have killed me when she found out.” He explains. Tanjiro ponders on the fact that he said ‘when’ and not ‘if’ but shoves the thought aside in favor of giving Genya a bright smile.

“Well, I’m grateful all the same.” He says with as much of a bow as he can manage. Genya shrugs one shoulder, scuffing a toe in the dirt and scratching at the back of his neck, looking a little flustered.

“S’no problem.” He mumbles, averting his eyes and Tanjiro can't help but beam at him, delighted.

“Hey, after they deliver our swords we should meet up somewhere.” He says excitedly, elated at the prospect of a new friend. Genya just blinks owlishly at him.

“O...kay.” He says, looking a little overwhelmed. Tanjiro glances up at the sky, noting the position of the sun.

“Well, I’d better get back to Urokodaki-san and my sister. Thank you again, Genya-san. See you soon!” Tanjiro says with a wave, watching as Genya gives his own little answering wave before he turns and starts walking in the opposite direction.

Tanjiro smiles to himself as he hobbles down the road, thinking back on how nice Genya had smelled. Like sandalwood and spices with just a hint of wood-smoke. It had been comforting to Tanjiro, almost calming with how much it smelled like home. He’s a little puzzled by the faint scent of ashes and blood that had come from the other boy, but they had just spent seven days running around a demon infested mountain, so he chalks it up to that.

He thinks about the traces of flowers and honey underlying Genya’s own scent and wonders if it isn’t the Sensei the other boy had talked about.

There’s a low stone bench at the foot of Mount Kita, a marker that indicates where the road starts to climb towards the summit.

It’s where Reimei had seen Genya off to the Final Selection exam and where, surprisingly, he finds her when he returns, still sitting on the bench as if more than seven days haven’t passed. At the sight of her Genya is struck with the thought that his teacher might never have re-ascended the mountain after he left, but instead waited here for him to return, evidenced by the blanket laid across her lap and the way her head is tilted forward so that her chin rests on her chest, her arms crossed over her stomach like she's dozing.

She must hear him approach, because he’s still fifty yards away when her head jerks up. For a moment it’s like Genya is looking at a stranger, every single day of his teacher's twenty years etched onto her face as wide green eyes stare at him before she seems to recognize him and her expression crumples.

She’s off the bench and down the road before he’s fully aware that she’s even moved, colliding with him hard enough to nearly knock him over. He staggers, steadying them both, but it isn’t until he's straightened slightly that he can make out the words Reimei is mumbling into the collar of his shirt.

“You came back. Thank the Gods. Genya, you came back.”

Genya can’t help but blink, shocked, when he recognizes the hot dampness of tears against his neck, but something about his teacher’s sudden loss of composure brings on his own, tears stinging at his eyes as his chest tightens, the rush of emotions brought to the forefront by the uncertainty and chaos of the past week.

He wraps his arms as tightly around his teacher as he dares, drops his head onto her shoulder, and starts to cry.

Chapter Text

The Mount Satagumo incident goes about as well as to be expected.

Which is to say, not very well.

Genya, who had stumbled across Tanjiro arguing with a boy wearing a boars head and a screaming blonde on the side of the road had, reluctantly, accompanied the trio to their next destination, seeing as his own crow had instructed him to head in the same direction.

What had followed could only be described as a cluster fuck of the worst kind.

They’d gotten split up (because of course they had) only for Genya to re-stumble upon the boar-headed kid, Inosuke, trying to hold his own against a huge, hulking mass of enraged spider-demon. The two had teamed up to take on the “father” until, backed into a corner, Genya had ripped a chunk off the thing’s shed skin and shoved it into his mouth.

Everything after that is a bit of a blur, but Genya is pretty sure he had driven his arm, gun and all, into the demon’s stomach, firing upwards to catch the heart and lungs.

But it hadn’t been enough. Inosuke had nearly gotten crushed and Genya was sporting a lot of superficial wounds when he’d felt a damp chill on the back of his neck.

The last thing Genya remembers clearly is blank blue eyes staring down at him in surprise before the darkness had rushed up to claim him.

Which is how he finds himself waking up trussed up like a roast, his cheek pressed against gravel and a shadow looming over him.


He’s pretty much fucked.

Tanjiro is still unconscious beside him, the Kakushi leaning over them trying, unsuccessfully, to wake up the redheaded boy.

Genya blinks, the harshness of the sunlight and the sharpness of his surroundings suggesting that he still has a lot of the spider demon left in his system. Every tiny shift makes him acutely aware of the bite of stone along his front, the rasp of fabric against his skin, the texture of the ropes tied tightly around his wrists. He can smell the scent of charcoal coming from Tanjiro, overlaid with ashes, blood, and the perfume of the evergreens in the bonsai garden. There’s a sharp tang on his tongue, not unlike citrus, but it’s muddled enough to make it hard to identify.

He rolls onto his side, groaning with the pressure the move puts on his arms, before slowly sitting up. His head protests and his eyes swim, but he squints through the discomfort.

Slowly, the rest of the yard comes into focus, revealing the eight people standing over them, and Genya feels all of the blood drain from his face.

He knows who these people are without having to be told, the near crushing aura of power that surrounds them making him shiver.

He’s temporarily shaken out of his stupor when Tanjiro wakes up, immediately starting to call out for his little sister.

But Genya can’t hear him over the roaring in his ears, because if he’s here to be ‘put on trial’, as the Insect Pillar had said, then he’s as good as dead.

Genya is very aware of what he looks like, how his eyes are demon red and his teeth are too long, too sharp to be human. He’s seen the effect eating demons has on both himself and his teacher, and it is no doubt damning enough to all of the Hashira present.

He is painfully aware of the rules and the consequences of breaking them, because no matter that they aren’t enforced on his teacher she isn’t here to run interference.

Which means he’s on his own with no hope of getting out of this alive.

Sanemi falters when he lays eyes on Genya, the manic smile he’d meant for Kamado slipping from his face, the wooden box in his hands hitting the ground with a dull thud.

It’s been years, but that doesn’t lessen the pain at all, especially when Sanemi notes the signs of demonification marring his brother’s face. His chest hurts something awful, a rushing sound filling his ears as the realization sets in.

If Genya has been turned into a demon…

But no, the sun is out and Genya is sitting up, not a burn to be seen.

Obanai, the asshole, is the one to oh so helpfully elaborate.

“Your brother ,” Oh, the fucker is enjoying this. “Ate a demon. You know the rules, Shinazugawa.”

Sanemi wants nothing more than to bare his teeth at the snake bastard, to snap and snarl at him until he shuts the fuck up, but other members of the Hashira are putting in their two cents.

“But, didn’t he do it to help? Do we really need to punish him?” Bless Kanroji for her gentle heart, but Sanemi has a feeling it’s not going to get them anywhere.

“What a pitiful child.” Himejima is crying, as per usual, even as he starts chanting sutras under his breath. 

“Eating demons is forbidden, and definitely not flamboyant!” Uzui’s voice is a deep boom across the yard.

“I’ll cut off his head so that Shinazugawa won’t have to!” Rengoku is almost as loud as Uzui, but at his words Sanemi feels his blood run cold, even as his hand falls to the hilt of his nichirin sword.

Like hell he’s letting anyone else touch his little brother, but rules are rules, and if Genya has gone this far…

He doesn’t want to think about it, but he’ll be damned if he stands by and lets someone else take on his responsibilities. 

“Like hell you will.” He growls, teeth bared.

“He broke a cardinal rule, Shinazugawa. You know the sentence is death.” Obanai is really asking for it, but Sanemi doesn’t even give the asshole a glance. Instead he steps forward, drawing his sword, and feels his heart shatter when Genya’s eyes widen in understanding.

If anyone is going to kill his brother, it’s going to be him.

Genya has a lot of regrets.

He regrets that he’s never going to get to apologize to Sanemi properly. He should never have accused him, all those years ago, should never have called him a murderer. He should have been a better brother, less of a burden.

He’s never going to get to thank Tanjiro for his kindness, brief though it was. They hadn’t known each other long, but the smaller boy had been a balm to Genya’s tired heart all the same.

He’s never going to get to make his Sensei proud. He’s never going to get to apologize and thank her for looking out for him, for teaching him even though he’s obviously a lost cause. He’s never again going to sit with her in an inn after days of traveling, drinking tea and braiding her hair as they listen to the cicadas sing.

No, he’s going to be executed here by his own brother as a ‘demon’, and he’s going to have accomplished nothing.

And the worst part is that Genya understands.

He doesn’t blame Sanemi. If anything, this is a mercy killing, his brother’s assurance that one of the other Pillars doesn’t drag out his inevitable execution.

But Genya still feels his chest tighten, his throat closing up as his tongue lays heavily behind his teeth with all the words he wants to say but can’t.

Tanjiro is struggling beside him against the Kakushi holding him down, screaming something that Genya can’t hear. All he can see is the green of his brother’s sword, glinting in the sunlight as it lifts above his head.

It’s going to be quick and clean, at least, and for that Genya is grateful.

He closes his eyes and waits for the blow to fall.

But it never comes.

Instead, there’s a roaring in Genya’s ears, like the howling of a storm, and then the ear-splitting clang of two swords clashing together.

Genya’s eyes snap open.

For a second he thinks he’s already dead, colors blurring together before his eyes, but then the familiar green and white haori of his teacher comes into focus and he nearly sobs with relief.

The two swordsmen strain against each other for a moment before Sanemi falters, seeming to recognize the woman standing before him. She presses her advantage, pushing him back so that he skids on the gravel, arms pinwheeling to regain his footing.

Stunned silence descends over the yard, as if everyone present is holding their breath. The moment stretches, distorting into discomfort, before Sanemi breaks it.


There are emotions in that one word that Genya hasn’t heard from his brother in years. They’re raw, flayed open, bare and broken in a way that makes Genya shiver, even as he twists his head to stare at his brother.

Sanemi looks like he’s been gutted, his eyes fixed on Reimei as if he’s seeing a ghost, eyes flitting across her face like he’s not sure it’s really her.

“You haven’t changed at all, have you, Sanemi?”

Genya feels his breath catch in his throat, surprise and disbelief warring in him, because there’s familiarity in his teacher’s tone, surprising intimacy in the way she speaks his brother's name without an honorific. But what’s truly telling is the way Sanemi flinches at her words, his whole body recoiling like she’s burned him.

“Rei…” He starts, but whatever he meant to say is interrupted by the arrival of the Master.

“Oh dear. I had hoped you would all get along in my absence, but it would seem that is not the case.” Ubuyashiki’s smile is mild enough, but Genya gets the feeling that he’s extremely disappointed in all of them.

He is startled from his musings by Tanjiro’s yelp as he’s forced to the ground by Sanemi, one scarred hand holding the boy’s head down. The Hashira all collectively drop to one knee, but Genya is interested to notice his teacher has remained standing, green eyes still just shy of too bright.

“You should show proper respect to the Master.” Himejima says, the first signs of anger starting to crease his face.

“I will bow my head when I am in the presence of someone who deserves that respect. Right, Ubuyashiki-sama?” Her voice is like a chill breeze and the Pillars seem to bristle at her comment, but all she receives from the Master is a kind smile.

“It is good to hear you are in good health, Kumeno-san.” Ubuyashiki says mildly and it takes Genya much longer than it should have to realize that he’s talking to Reimei. He blinks, glancing at his teacher, before Tomioka interrupts.

“Kumeno? Like Kumeno Takashi, the former Wind Pillar?” He asks, uncharacteristic surprise in his voice.

Ubuyashiki’s smile is small and secretive.

“The very same.”

It all happens so fast that Genya isn’t quite sure what happens in what order.

All he knows for sure is that his brother and Tanjiro are both bleeding and his arms are full of a small demon girl, her pink eyes creased in pain.

Tanjiro had been shouting in anger, yelling that if the Pillars couldn’t even tell a good demon from a bad one that they should quit being Hashira. Sanemi had gone for Tanjiro, rage etched across his face, except his sword had never touched the boy, the door to the wooden box he'd dropped slamming open with enough force to bounce off of the gravel. Nezuko, tiny and dark haired and growling, had thrown herself between her brother and Sanemi, despite the burns that had blossomed across her skin and the nichirin blade aimed for her throat.

The next few seconds were a blur as Tanjiro had screamed and tackled his sister right before Reimei had grabbed both kids by the scruff of the neck and shoved them at Genya. Now he’s crouched in the shade of the engawa, Nezuko whimpering in his arms and Tanjiro panting at his side while his teacher turns flinty green eyes on the Pillars.

“Pathetic.” Her voice is a sibilant hiss, forced out between clenched teeth and Genya can’t help but shiver.

He’s seen his Sensei truly angry before, lost to rage and bloodlust in the heat of battle. In those instances he knows that the more irate she is the less articulate she becomes, almost as if her heightened emotions rob her of the ability to speak.

But this is different, a cold chill crawling under his skin as his teacher’s killing intent rolls over him as an almost physical touch. It’s like being trapped in a storm, the wind piercing through him like a thousand icy needles.

“Is this how far the infamous Hashira have fallen?” She spits the title like a slur. “Reduced to turning their swords on humans?”

“The brat protected a demon, whether or not she’s his sister is irrelevant.” Obanai is quick to point out. Reimei sneers at him, teeth bared.

“And I don’t see either of them attacking indiscriminately like a bunch of savages. If we draw our swords in hatred and turn them against the innocent, regardless of their species, then what makes us any better than the ones we claim to hate?”

A tense silence falls over the gathering as Obanai narrows his eyes and turns to face Reimei fully, his arms dropping to his sides almost as if he is contemplating drawing his sword.

“That is quite enough.” Ubuyashiki has remained silent up until that point, but at his words Obanai immediately backs down, turning away with a scoff.

“Sanemi, even as you were bleeding Nezuko chose to rush to her brother’s defense instead of attack you. Even now she makes no move, despite being in the presence of a marechi.” Here, Ubuyashiki tilts his head slightly. 

“I believe this is sufficient enough evidence that Nezuko will not attack humans in the future.”

There is a long moment of silence before those Pillars who had initially objected bow their heads. Obanai is the last, eyes narrowed even as he nods his ascent.

“What about Shinazugawa Genya? He still broke the law by eating a demon. What are we going to do with him?” He asks, for all the world sounding like a petulant child.

“Touch one hair on my student’s head, Iguro, and I will relieve you of your arms.” Genya gulps, holding Nezuko a little closer, because his teacher delivers the threat without any kind of inflection whatsoever, as if she’s simply commenting on the weather.

He knows with absolute certainty that she’ll go through with it, too.

Obanai has turned to glare at her, no doubt preparing to deliver a scathing retort, when Ubuyashiki interrupts again.

“Genya-kun has special permission, just like the Kamado’s. His health is being monitored by both his Sensei and Shinobu. If you have any major concerns, then feel free to inquire with either of them.” The words are bland enough, but Genya can tell that the conversation is over.

It is with mixed emotions that he follows his teacher from the garden.

On the one hand, he wants to stay and talk with his brother, but on the other he is simply relieved to leave the Pillar meeting alive.

Nezuko, once more safely in her box, and Tanjiro are being carried off to the Butterfly Estate by two Kakushi, the redheaded boy waving to Genya as he disappears around a corner. Genya drops his arm from where he’d returned the gesture before turning to glance at his teacher out of the corner of his eye.

Green eyes meet his own, calm and steady.

“I’m afraid the answers to your questions are going to have to wait, Genya-kun. We have work to do.”

He nods and falls into step with her as they set out.

Chapter Text

Genya concentrates on putting one foot in front of the other, diligently following the little calico cat that prances at the head of their odd procession. Behind him is Tanjiro, carrying Nezuko in her box and supporting Zenitsu with one arm, Inosuke limping at the rear. 

Genya is ever aware of the shallow breathing of the unconscious Pillar on his back, the slow drip of blood down one limp arm, and the fact that they are quickly running out of time. No doubt, if the sun hadn’t broken through the trees when it did then not just Kyojuro, but all of them would have been killed by Upper Moon Three. 

He can still recall with perfect clarity the frisson of icy cold fear that had lanced through his veins at the appearance of the Upper Moon, the overwhelming pressure of Akaza’s aura like a physical weight upon his shoulders. Just watching the Hashira and demon clash had been chilling, their movements almost too fast to follow. Despite his fear, Genya had snatched up one of Akaza’s dismembered limbs and quickly sunk his teeth into cooling flesh, determined to back Rengoku alongside Tanjiro. 

But it had eventually been the sun that had driven the Upper Moon away and Genya can’t help but feel a pang in his chest at the depths of his own weakness. He’s still riding the high of eating an Upper Moon, energy buzzing under his skin like an electric current, but he can already tell that the come down is going to be brutal. His muscles are just starting to cramp, every limb beginning to ache something fierce, his head throbbing with every step he takes. 

Still, he continues to follow the cat, determined to protect the man who had put his life on the line for all of them. 

Eventually, the woods thin until the six of them are stumbling onto the edge of a town, the sloping hill before them bisected by the dirt road that runs directly through the center of the settlement. The cat has stopped at the bottom, at the very first house which is set a good hundred yards from the main thoroughfare. The sun is still fairly low, but there’s the bustle of early risers starting to echo from the village, so they hurry down the hill as best they can and sidle up to the front of the house, Genya keeping his back towards the building in the hopes that no curious onlookers notice the heavily bleeding man draped across his shoulders. 

Tanjiro hasn’t even managed to lift his hand to knock when the door is yanked open, an irritated looking boy glaring at the group huddled on the doorstep. They all stand there in silence for a moment before the boy huffs and steps aside. 

“Should have known you couldn’t keep yourself out of trouble, Demon Slayer.” He spits at Tanjiro, even as they all crowd into the genkan and start shuffling off their shoes. 

“Sorry to barge in on you, Yushiro-san.” Tanjiro says with a strained smile. The boy, Yushiro, rolls his eyes. 

“Bring the injured this way. Tamayo-sama will see to them.” He says tersely. 

Genya dutifully follows Yushiro’s instructions, padding down a long hallway into what looks like a cross between an office and the infirmary at the Butterfly Estate. An older woman who he assumes to be Tamayo is waiting for them, finishing the ties on her apron as she starts directing them all to separate beds.

When Genya finally lays Rengoku down he see the crease in Tamayo’s brow deepen, before she quickly turns to Yushiro and starts issuing rapid fire instructions. 

Genya shuffles out of the way, watching in amazement as the two demons start tending to Kyojuro’s wounds. An hour later, however, and Tamayo’s expression has not smoothed at all. 

“I cannot do anything else for him.” She says softly as she moves to Tanjiro’s bed. 

“But…” Tanjiro looks devastated, his face seeming to collapse in on itself at the news. Tamayo shakes her head sadly. 

“There is too much internal bleeding. His organs are bruised, exacerbating the problem, not to mention the fact that his left eye is beyond saving and his right hip is practically shattered. I’m sorry, but his injuries are beyond my abilities to heal.” 

Zenitsu and Inosuke are uncharacteristically silent even as Tanjiro sniffles, wiping at his eyes desperately. 

“How long?” He asks, voice shaking. Tamayo has just opened her mouth to speak when Genya interrupts. 

“Can you keep him alive for a few more days?” He asks. 

“Don’t interrupt Tamayo-sama!” Yushiro snaps, but Genya ignores him, watching Tamayo carefully. She blinks, then nods. 

“I can, but it will only prolong his suffering.” She says and Genya nods. 

“I need paper, a pen, and some ink, please.” He says. 

“What for?” Tamayo asks curiously. 

“If you can’t save Rengoku-san, then I need to send for someone who can.” Genya says bluntly. 

“Um, Genya-kun, I don’t think it’s a good idea to invite Kochou-san here.” Tanjiro says nervously and Genya snorts. 

“Obviously. That’s why I’m not sending the letter to her.” 

A moment of tense silence follows before Tamayo seems to come to a decision and nods, face set. 

“Yushiro, please fetch my writing desk.” 

Tanjiro’s stomach wound requires extensive stitching, but other than Zenitsu’s head wound and a few fractured ribs there aren’t any outstanding injuries other than Rengoku’s. The Pillar sleeps deeply, but all of them are ever aware of his shallow breathing, one or all of them watching over him through the night.

Genya finds himself annoyed, more often than not, seeing as the three younger Demon Slayers are a lot louder than he’s used to. But he supposes the exuberant company is better than being alone, so he sucks it up and sleeps on the extra cot an irritated Yushiro had dragged in from another room. 

And thus two long, agonizingly slow days pass. 

Genya is sitting on the floor with Nezuko, playing a game of shogi while her brother, Zenitsu, and Inosuke chat among themselves about the training they’re planning on doing once they heal up. It’s nearing sundown when there’s a knock on the front door. Yushiro, who is changing Zenitsu’s bandages, makes as if to get up but Tamayo waves him away as she goes to greet their guest. 

Genya moves one of his rooks and looks up as the door slides open. 

His teacher doesn’t speak, but she crosses the room in a few quick strides and leans over him, her hands moving to cup his face. He sits silently through her inspection, letting her reassure herself that he’s okay before stepping back, apparently satisfied. 

“Genya-kun told me that Rengoku-san’s injuries are extensive.” Here, Reimei addresses Tamayo, who nods. 

“Internal bleeding, bruised organs, and multiple broken bones. Unfortunately, he is beyond my ability to help.” She elaborates. Reimei nods, eyes traveling to the bed at the far side of the room, it’s occupant unmoving except for the steady rise and fall of his chest. Something unreadable passes over her face before she takes a steadying breath of her own and turns her green eyes to meet Tamayo’s. 

“Please give Rengoku-san a transfusion of my blood, Tamayo-san.”  

Tamayo blinks, obviously confused. 

“I don’t understand how that is going to help. A blood transfusion isn’t going to heal the trauma his body has endured.” She says slowly. 

“My blood is special. Not in the sense of a marechi, but I am unlike the humans you usually treat, Tamayo-san. I can explain more, but I would prefer if we began the procedure as soon as possible.” Reimei explains. The doctor remains frozen for a moment, a myriad of emotions flickering through her eyes, before she slowly nods. 

“Very well.” 

Tamayo sets Reimei up in a chair at Rengoku’s bedside, the tube leading from her arm to his standing out starkly against the white of the clean sheets as her blood passes through it. When the doctor had asked what blood type she had, Reimei had simply smiled at her. 

“Not to worry, Tamayo-san, I’m a universal donor.” 

As the doctor works Reimei’s eyes flit to Genya then sweep to Tanjiro, Inosuke, and Zenitsu before finally settling on Nezuko, who is watching her curiously. 

“They know I can eat demons, Sensei.” Genya says softly, drawing her attention. Her shoulders drop a little and she nods.

“I see.” And she does, because Genya’s assurance means that he trusts the others, which is good enough for his teacher. 

"I would like to begin by saying that I mean you and yours no harm, Tamayo-san." She says gently. The doctor's eyes slide to her, questioning, and Reimei shrugs one shoulder.

“I am like Genya-kun in that I can eat demons without any ill side effects.” She explains. Tamayo goes temporarily stiff before, slowly, her shoulders ease and she inclines her head.

Reimei turns back to the kids, all listening intently, and continues. 

“But I have been doing so for a lot longer than Genya-kun, which means that my blood has changed over the years. It now permanently carries a few demonic traits that are beneficial to me, such as accelerated healing. And, if given to someone else like this,” Here she indicates her arm where the transfusion tube is attached. “Then that person will temporarily gain those same traits. It’s not nearly as effective as a real demons and it will no doubt take a few days, but it will be sufficient to ensure the majority of Rengoku-san’s injuries heal.” 

"That's...amazing." Tanjiro breathes out, eyes wide. Reimei's smile is strained.

"Indeed, which is why I don't imagine I need to tell you all that this information shouldn't be shared on a whim." She says dryly. 

"Why's that?" Zenitsu pipes up, obviously curious.

"Like Genya-kun, I am unique among the Demon Slayer Corps. If this information were to become widely known, then no doubt I would become a target for demons and humans alike. In effect, my life would be forfeit." She says gently, even as the weight of her words settles around them like a shroud. No one has anything to say to that, so the transfusion finishes in silence.

Finally, Tamayo unhooks the tube, removes the needle, and presses a cloth to Reimei’s arm, which she holds in place while the doctor packs up the rest of her equipment. Rengoku still hasn’t stirred, still deep asleep. 

When Tamayo straightens up Reimei bows to her from her seat. 

“I thank you for looking after this whole lot, Tamayo-san. I’m sure they gave you a great deal of trouble.” She says with a small smile. Tamayo’s answering smile is also small, but genuine. 

“Not so much that I can’t handle.” She says, before returning the bow and going to put her equipment away.

They leave Tamayo’s the next day, the doctor and Yushiro explaining that they’d already planned on moving on to the next town before the Demon Slayers had shown up on their doorstep. Reimei leaves for an hour and returns with a horse, a small cart hitched behind it onto which they load Rengoku, who is still unconscious. Tanjiro and Zenitsu are, after a lot of arguing, unceremoniously slung up onto the saddle by Reimei, leaving Genya to carry Nezuko in her box and Inosuke to trudge along behind them. 

They’re barely an hour into their journey when the boar-headed kid starts harassing Reimei to fight him, going to far as to try and draw his swords until, finally fed up with his antics, Genya hits him over the head and tosses his limp form over the horse’s rump behind Tanjiro. 

They make good time back to headquarters after that, both Reimei and Genya used to the long days of travel. They’re met at the gates by Shinobu, who takes all of the injured with her to the Butterfly Estate, horse and all. 

It takes another five days for Rengoku to wake up and when he does he’s just as boisterous as before, albeit a little slower. Tanjiro, Inosuke, and Zenitsu all cry over him when the Kakushi rush out to spread the news, the noise alerting Genya to the Pillar's return to consciousness. Kyojuro is missing an eye and his previously shattered hip means he’ll never have the same range of motion as before, but his retirement is approved by Ubuyashiki with a marked sense of relief. 

Everyone is painfully aware that in any other circumstance they would be holding a funeral instead of a retirement party, even if Rengoku grumbles about having to hang up his swords so soon. 

Tanjiro is still at the Butterfly Estate, recovering, when Genya witnesses something he probably shouldn’t have. 

He’s heading for his teacher’s rooms at the Kinoe barracks in preparation for their next mission when he pauses at the sound of familiar voices up ahead. Cautiously, he approaches the corner and stops to listen. 

“...dn’t be here.” He’s surprised by the inflection in his older brother’s tone because he sounds more like he’s speaking to a family member than a subordinate, the harsher edge gone from his voice. 

“Yes, well, none of us got much of a choice , did we?” Genya winces at the venom in his teacher’s voice. He chances a peek around the corner and sees them halfway down the corridor, Sanemi’s mouth twisted into a frown and Reimei’s face oddly blank, a good indicator that she’s exceptionally angry about someting. 

“Rei…” Sanemi’s whole form seems to sag, but she cuts him off. 

Don’t.” It’s more a growl than a word and Genya knows he’s not imagining it when his brother flinches. 

“You lost the right to give your opinion about my actions a long time ago, Sanemi.” Reimei’s face is hard, jaw set and expression stony. 

“After all, you’re the one who abandoned me.” 

“I did it to protect you!” Sanemi’s voice is immediately back to harsh and loud, his face contorting with emotion as he takes a step forward, but Reimei bares her teeth at him, eyes alight. 

“Liar! You ran away! You ran away from me just like you ran away from your brother!” Genya can clearly see her anger, brows creased and mouth twisted, but he can also see the glimmer of tears at the corners of her eyes, the tremble of her hands and his heart goes out to his teacher. 

Genya jumps when Sanemi suddenly surges forward, slamming Reimei up against the nearest wall, hands fisted in the front of her uniform. 

“How dare you!?” He’s right up in her face, snarling, but Reimei’s face is determined, her form unflinching. 

“Tell me I’m wrong, then. Explain it to me.” She challenges him, eyes darting between his own, as if she’s searching for something. 

They remain frozen like that for a moment, Sanemi looming over her, nose scrunched up and teeth bared, before Reimei’s shoulders sag, her face seeming to crumple. 

“Tell me why you left me behind.” Her voice is soft, cracking, and Genya feels his chest ache at the expression on his teacher’s face. An unbearable sadness has settled across her features, her eyes suspiciously wet and her brows drawn together, open and vulnerable in a way that Genya has only seen a few times. Sanemi’s expression, too, changes, morphing into something softer, uncertain. 

But he doesn’t answer her and, after a moment, Reimei lets out a shaky breath. With deft fingers she plucks Sanemi’s hands from her shirt, stepping to the side to walk around him. Sanemi lets her go, watching her as she heads down the corridor. 

At the far corner she stops, but she doesn't turn to face him. 

“If you really want to make amends,” Her voice is soft, barely audible in the quiet hallway. 

“Then apologize to Genya, first.” 

And then she’s gone, disappeared around the corner like a ghost.

Genya, reeling, turns and, as quietly as he can, makes himself scarce, missing the shaky exhale that Sanemi lets out as he slumps heavily against the wall, his head falling back against the wooden surface with a solid thunk.

Slowly, the Wind Pillar slides down the wall to sit on the floor, crossing his arms over his raised knees and letting his forehead come to rest against his scarred forearms, hiding his face as the hot burn of tears overflows from behind his bloodshot eyes.

Chapter Text

Reimei knocks once on the door before sliding it open. Instead of continuing on into the room beyond, however, she stops short, causing Genya to almost run into her. Curious, he glances over her shoulder. 

He has to clench his jaw tightly to prevent any kind of rude noises from passing his lips because “homely” is the nicest term available to describe the three girls sitting seiza on the floor, even if something familiar is niggling at the back of Genya’s mind. All three of them are wearing garish makeup and mismatched kimono, clustered around a man Genya recognizes as the Sound Hashira. 

In front of him, his teacher twitches and makes an odd, distorted wheezing noise and Genya steps around her properly to see that her face is scrunched up, her lips pressed so tightly together that they’re turning white, her cheeks puffing up as she fights not to laugh. For a moment Genya is confused, but then the redheaded girl notices him and greets him with a wave.

“Hello, Genya-san!” 

A very long moment passes where Genya’s brain tries to process where, exactly, he’s met this person and heard that voice before, and when it finally clicks he nearly falls over. 

Tanjiro!? ” 

His outburst is the catalyst for his Sensei to double over, both arms crossed over her stomach as she clutches her sides and laughs, great wheezing guffaws that bring tears to her eyes and seem to steal the air from her lungs. 

“What’s so funny?” Uzui seems a little offended and Reimei waves a hand through the air as she continues to gasp for a proper breath, one hand clamped over her mouth as she tries to stifle the laughter. 

“Uzui...Uzui you can’ can’t mean to send these boys to Yoshiwara like that?” Her mouth is wobbling as she straightens, wiping tears from her face as she trails off into chuckles. Uzui’s mouth twists in a pout and she grins widely at him. 

“Uzui, no. No, you can’t.” She enters the room properly, then, kneeling by the three “girls” and taking up a cloth to wipe at Tanjiro’s badly painted face. 

“Genya-kun, please ask the house aid to bring back the makeup kit and a few different kimono.” She instructs as she hands cloths to Inosuke and Zenitsu, instructing them quietly to clean their faces. By the time Genya has returned with the requested kit, Uzui is glaring at Reimei. 

“...ith it?” He’s asking. Reimei throws him a pitying looks and accepts the makeup kit from Genya with a soft ‘thank you.’

“Honestly, Uzui,” She says, tone teasingly light as she beckons Inosuke forward so she can start running a comb through his hair. “You took a perfectly pretty boy and turned him into one of the ugliest people I’ve ever had the misfortune of seeing with my own two eyes, regardless of gender.” 

As she starts setting out pans and brushes and an assortment of tools that Genya can’t even begin to wrap his head around, the house aid knocks on the door. Reimei glances over the kimono he’s brought with a critical eye. 

“The green one with the dark purple obi for Inosuke. Pink with the white for Tanjiro. Dark blue and that gold obi with the flowers for Zenitsu.” She says, leaving no room for argument as she points out each selection. 

Twenty minutes later and Reimei leans back with a little satisfied smile while Genya has to turn his bright red face away. 

Inosuke’s already fine features have been accented by subtly painted lips and minimal eye makeup, putting his fine bone structure on full display. Zenitu’s hair has been swept back to accentuate his rounder face, the area around his eyes painted with kohl to make them seem brighter and more dramatic. And finally, Reimei had expertly blended out Tanjiro’s makeup to hide his scar, painting his lips a pretty pink and fixing his lashes to make his large eyes appear even larger. 

It gives the redhead an altogether innocent look, one that makes Genya’s heart trip in his chest. 

Uzui is staring at the three of them, a flabbergasted look on his face. 

“How did you…?” He trails off, side eyeing Reimei, who is smirking triumphantly. 

“Your wives do all the work, don’t they?” She teases and Uzui pouts. 

“What are you even doing here?” He grumps. 

“Waiting on the hairdresser.” Reimei responds. Uzui’s brows draw together. 

“What for?” 

“Ubuyashiki-sama is sending me to Yoshiwara as well.” Reimei must read the annoyed look that passes over Uzui’s face, because she continues without giving him a chance to interrupt. 

“As a precaution, of course. Turns out we’ve had reports from around the area since Ubuyashiki-sama’s great-grandfathers time. So, whatever is living in Hanamachi, it’s old.” 

The Sound Hashira continues to frown at her before blowing air out between his teeth in a frustrated sigh. 

“What house?” 


Genya hates the shoes the most. 

Sure, the yukata is slightly more restrictive than his uniform and it’s just plain odd to not be wearing pants after so long, but he’s grown accustomed to the protection his boots provide and so he absolutely hates the sandals he’s been given. They pinch right between the toes, which is irritating as all hell. On top of that, he’s extra twitchy without his sword at his side, despite having his gun tucked into the folds of his clothes. 

He has to keep reminding himself that his teacher has it worse. 

Reimei is wearing at least a dozen layers, all borrowed from the Sakaki house, rich silks in vibrant colors that make her appear like a bright spot amidst the crowd. The fifteen centimeter geta make her walk excruciatingly slow which means he, acting as her attendant, has to match the same slow pace. He doesn’t really mind her left hand resting on his shoulder or the warm comfort of her presence, but he keeps side-eyeing the people around them. 

The only thing that’s dramatically different about her is that the hairdresser had temporarily colored her hair black before putting it up, the waxes making it stiff and shiny, but the change is enough to make her green eyes really stand out, to the point that they’re bright enough to glow even in the afternoon light. 

Genya has watched at least three men run into things while staring at his Sensei and half a dozen women stop and do a double take just on this section of road. 

He’s not entirely sure why. He knows his teacher is pretty enough, but he’s been around her long enough to see her at all possible stages of unkempt, so perhaps he’s just gone blind to it. 

Regardless, it takes them another ten minutes to reach the tea house where they’d agreed to meet with Uzui. 

As custom dictates, Reimei sits on the opposite end of the room from the Sound Hashira, her cups and plates empty while he orders dinner for himself. It pisses Genya off, but as the lowest ranking member in the room he keeps his mouth shut. 

Finally, Uzui knocks back the last of his sake and levels Reimei with a blank stare. 

“Suma and Makio are missing, but I’ve got a lead on Hinatsuru.” 

“I assume, if you’re speaking plainly, then we don’t have to worry about prying ears?” Reimei asks, head tipping forward. Uzui nods. 

“I’m headed to the poor houses.” He says and Reimei nods. 

“I’ll look after the brats while you’re gone, then.” She says, indicating for Genya to help her stand. 

Uzui stops them before they can leave the room, his eyes serious. 

“I haven’t been able to confirm my suspicions, but...I think we’re dealing with an Upper Moon.” He says softly. 

Genya swallows thickly, his fingers tightening on his teacher’s arm. She draws his attention by gently patting his hand, smiling at him when he turns to her. 

“Whatever happens, Uzui.” She says, eyes flicking to the Sound Hashira. 

“The children’s lives come first.” 

Uzui remembers Kumeno Reimei as a scrappy little redhead with fire dancing in her eyes and a symphony in her heartbeat. 

Years before, only a few months after Shinazugawa had been promoted to the position of Hashira, he and Himejima had been sent by the Master to investigate an odd phenomenon. Reports of demons would come in but, by the time a member of the Corps was dispatched to help, the threat would have already been taken care of. Residents of the area would always report a person wearing something like a slayer uniform showing up right before the demons disappeared, too, which cast the whole situation under another layer of suspicion. 

According to Ubuyashiki, the reason two Pillars were being sent was because they didn’t know who was eliminating the demons and they couldn’t be sure that whoever it was would take their approach well, regardless of their good intentions. 

After all, the adage “the enemy of my enemy is my friend” didn’t always hold true. 

But Uzui should have guessed that the Master already knew what was going on. 

While Himejima had wandered the streets, acting out the role of a traveling monk, Uzui had taken to the rooftops, which is probably why he found her before the Stone Pillar did. 

He’d been surprised when the person they were looking for had turned out to be a tiny slip of a girl wearing a too-big Demon Slayer uniform and carrying a nichirin blade at least two hands too long for her. 

A lot of Uzui’s memories are fuzzy, but he distinctly remembers her eyes, how they’d sparked and burned with a determination that he’d nearly felt as a physical touch. They’d zeroed in on him immediately, too, like he was the only person besides her on the road. 

And she’d been fast. 

He’d chased her from the village, keeping up with a surprising amount of difficulty. They’d moved lightning fast through the forest at the edge of town, dodging around and over trees at breakneck speed. Uzui had felt alive in that moment, his blood thrumming with adrenaline, and he’d thrilled at the sounds he’d been getting from the girl, a harmonic rhapsody the likes of which he had never heard before from a living person. He could tell that every breath was measured, every step practiced and easy, every movement made with purpose, even if that purpose was driven by instinct. 

And then she’d twisted in mid-air to avoid a blow from his swords, catching one of the links of the connecting chain with the tip of her sword, and had driven the whole thing into the trunk of a nearby tree with surprising strength. 

Uzui had yanked, trying to free his weapons, but had found them immovable, the green-bladed sword stuck fast nearly to the hilt. One of the girl’s feet was also shooting for his head, so he’d dropped his trapped swords and chosen to dodge, hearing the sharp whistle as her ankle passed by his ear. 

Elated, he’d landed with a solid thud and laughed. 

“Girl, that’s some impressive footwork. What’s your name?” He’d been eager, wanting to know how one so young could fight so well, but she’d remained tight lipped, obviously thinking his words some kind of trick. 

A loud clap made both of them jump, Himejima appearing through the trees, his prayer beads hanging from his hands. 

“Kumeno Reimei, we mean you no harm.” 

Uzui had been surprised to see the girl's shoulders, before held in a tight line, draw up even farther at Himejima's words. She hadn't taken her eyes from Uzui, but he'd known she was ever aware of the Stone Pillar's approach.

Embarrassingly, it had taken Uzui another few moments to put all the pieces together.

The girl shared, while not the features, but the surname and certainly the skills of the former Wind Hashira, Kumeno Takashi. That, coupled with the too big Corps uniform and a sword obviously forged for a taller person, made realization curl sickly and acidic in his gut.

"Is Takashi-san..." He trails off as he sees the girl flinch, his lips pressing together even as she opens hers.

"My father is dead." Her voice is flat, tone even, but Uzui can hear the skip in her heartbeat, the way her breathing stutters in her chest.

For him, her grief is as plain as day, and it makes his chest ache in sympathy.

Himejima nods in understanding.

"Oyakata-sama suspected as much. He would like to offer you a place amidst the Demon Slayer Corps." He says.

Uzui, who had expected Reimei to immediately agree, is surprised (again) when she pauses, something sharp and unfamiliar flickering to life in her eyes, a coldness that had sent a terrible shiver down Uzui's spine.

"I have conditions." She'd finally said.

The entire exchange had left an odd feeling in Uzui's gut, a nagging feeling of unease and tension that hadn't gone away for some time.

It's only now, staring up into blood-red eyes, that he fully understands what it was.

Somewhere, in the depths of his subconscious, something within him must have recognized the presence of a higher predator, the shift from human to something "other" that had set alarm bells ringing in his head, because the unfamiliar melody he's getting now is the same one he'd heard all those years ago, echoed by Shinazugawa's younger brother at her side. It's unlike the sounds a demon makes, something he can pick out from among the masses with ease. It's like a distortion, a crackling along his nerves that raises the hairs at the back of his neck, somewhere between a low pitched whine and garbled bird song.

Reimei shifts on the balls of her feet, blinking long and slow, and Uzui stiffens, prepared to defend himself if necessary.

"You look like shit, Uzui."

He freezes and stares at her with his one good eye, because, while he certainly wasn't expecting that, he's not going to let it slide.

"It's an Upper Moon." He defends, motioning towards the demolished buildings all around them. One of Reimei's eyebrows goes up.

"Is it?"

While he would ordinarily laugh at her sass, at the moment Uzui does not appreciate it.

"I'd like to see you do better!" He snaps, the chain of his swords rattling as he shifts his grip to better accommodate his one remaining hand. She grins, showing off every single one of her suddenly sharp teeth.

"With pleasure. Genya!"

Uzui doesn't falter as they throw themselves back into the battle, but he does make note of the change in Reimei's sound.

It's like a deep thrumming, a beat he can feel in the back of his throat as her heart settles, and he focuses on it as he falls into step with the two red-eyed Demon Slayers.

Like war drums in the dark, he follows them into hell.

Chapter Text

Genya stares out at the decimation of the red light district and feels his heart squeeze in his chest. 

Entire buildings lay in ruins, the moans and wails of the injured and the dying carried on the wind like a haunting echo. He can see Kakushi scuttling over the rubble like insects, pulling living bodies as well as the dead from under piles of roof tiles and splintered, charred timbers. 

The battle had dragged on for so long that the Eastern sky is just beginning to lighten, pink and orange starting to stain the horizon, and while the two Upper Six’s have been turned to dust there are enough casualties to sour the victory. 

With a heavy sigh Genya starts to pick his way through the wreckage towards where he last saw his Teacher. 

He finds her with Uzui, who is being supported by his three wives, and Iguro, who is overseeing the cleanup. She’s watching closely as Inosuke, Zenitsu, and an unconscious Tanjiro are all loaded onto stretchers, a child-sized Nezuko clutching at her skirts. While Reimei had abandoned most of them when the fighting started she’s still wearing a few layers of silk, though some of them look the worse for wear. Her hair, while still uncharacteristically black, has come mostly undone, a single kanzashi left from the original ornaments. She’s barefoot, her toes covered in dirt and blood, but she seems entirely unconcerned with her state of dress.

As Genya approaches, a Kakushi appears from around a corner, holding what is left of the box Tanjiro uses to carry Nezuko. The straps are broken and it’s badly singed, but apparently it’s still light tight as Reimei helps Nezuko climb inside it. 

Once the box is entrusted to the waiting Kakushi, Reimei finally turns to face Genya and seeing the extent of her physical state makes him suck in a sharp breath. 

There are dark circles under his Teacher’s tired eyes, blood stains splashed liberally across the front of her tattered clothes, yellowing bruises and scabbing cuts littered over her pale skin. Her hands shake with fatigue, her head dipping a little with each exhale, as if she might nod off where she stands. But she still manages to smile at him as he comes to a stop beside her. 

“You’re alright.” The relief in her tone makes his chest hurt, his insides squirming, but he nods. 

“And you?” He’s concerned and doesn’t try to hide it, but she shakes her head. 

“Nothing a little rest won’t fix.” Her smile is strained and he frowns. 

“I’ll help.” He announces, spinning on his heel and dropping quickly to one knee. Reimei’s head tilts in confusion, her mouth opening to no doubt ask what he means as he looks over his shoulder at her, arms slightly extended at his sides in obvious invitation. 

“I’ll carry you, Sensei.” He says, voice firm, and her face softens. 

“Genya-kun, you don’t…” 


She freezes, green eyes searching his face. Finally, her shoulders sag and she sighs, stepping towards him so that she can climb onto his back. Hooking his hands under her knees he stands, her arms going around his shoulders to steady herself. 

“When did you get so tall, Genya-kun?” She yawns as he starts walking, eyes drooping heavily as the extent of her exhaustion seems to finally catch up with her. 

“I don’t know. After Final Selection, maybe?” He says absently, falling into step with the Kakushi who are carrying Tanjiro and the others, following them away from the destruction that is Yoshiwara. 

He feels his teacher hum against his back, her cheek coming to rest against his shoulder as her whole body goes slack and she closes her eyes, her breathing evening out into the familiar pattern of sleep almost immediately. 

Genya is both relieved and concerned. 

He is absolutely certain of his Teacher’s strength, of her determination and will, but seeing her push herself so far had frightened him more than he’d thought. 

He vows then and there to work harder so that he’ll be better prepared to protect her in the future. 

Mount Kita looms over them, the late afternoon sun painting it in a brilliant swath of color. 

Or, at least, Sanemi thinks so. To him, it’s just different shades of gray, all tinted with the barest hint of muted color. But from what he remembers, the mountain is probably awash in orange and gold, the colors of early fall magnified by the setting sun. 

He trails after Masachika up the mountain road, mulling over everything the older boy had told him about his new trainer, Kumeno Takashi. A former pillar, now retired, Masachika had seemed excited at the prospect of introducing them. Sanemi isn’t so sure, but this is his best course of action if he wants to get better at killing demons. 

Soon enough, a house appears through the trees, smoke curling up from the roof to dissipate amidst the branches overhead. There’s a person moving around in the garden beside the house, wearing what Sanemi thinks might be a deep green kimono and carrying a basket on her hip. He doesn’t get a chance to look closer because Masachika suddenly lets out an excited whoop and picks up his pace, startling Sanemi. The Demon Slayer’s exclamation in turn makes the girl jump, her head turning sharply towards them. 

Sanemi's limited perception means that he can't tell the exact shade of her hair, but he knows that it's vivid, whatever it is. The lightness of her eyes makes him think they might be a bright, verdant green, but, again, he isn’t sure, but he’s perfectly placed to watch her whole face light up at the sight of Masachika, breaking into a wide smile. 

“Masachika-nii!” The basket is dropped, abandoned amidst the garden rows as she runs towards them, the two siblings colliding in an enthusiastic hug. When they pull apart it is only so far that they can be face to face, immediately starting to chatter excitedly to each other, their voices harmonizing even as Sanemi stands awkwardly by. Seeming to realize this, Masachika turns to him with a near blinding smile, hand outstretched. 

“Sanemi, come meet my little sister.” 

Sanemi can vividly recall every detail of this version of Kumeno Reimei, from her wide, warm smile and soft eyes to the way her hair had been carefully pulled up, shorter locks falling to perfectly frame her pretty face. 

"It's nice to meet you, Shinazugawa Sanemi."

Sanemi sucks in a sharp breath as his eyes snap open, the memory dissolving as he is thrust rudely back into the waking world. With a heavy sigh he drags a hand down his face and uses the other to push himself up off the floor where he’d fallen asleep, scrubbing at his eyes in a vain attempt to force his mind onto something else. 

He quickly becomes aware of a commotion outside the gates of the Wind Estate, which must have been what woke him.

Dragging himself up and out the front door is a chore, but all lingering vestiges of sleep vanish when he emerges to a cacophony of activity along the main thoroughfare that winds through the Demon Slayer Headquarters. 

Kakushi are running every which way, crows flapping overhead like fluffy black clouds. Curious and a little concerned, Sanemi follows the stream of activity, which eventually leads him to the Butterfly Estate. 

Shinobu’s Tsugoku, Kanao, is standing outside the gates, directing traffic. While a lot of it is medical jargon far beyond him, from the hubbub of voices Sanemi can pick out such words as “acute trauma” and “amputation” which all sound bad enough that he picks up his pace. 

A sense of dread settles in the pit of his stomach, because only one Hashira was out on an active mission and, according to his reports, Uzui had not only taken Kamado and his sister along, but Reimei had been sent by the Master as well. 

Which meant Genya had been there. 

That realization puts Sanemi on high alert, scanning every hall he passes for a head of black hair and a purple yukata, but it isn’t until he’s deep within the estate that he finds him. 

For a moment, Sanemi isn’t sure what he’s looking at, because there’s a strange lump draped over his younger brother’s back, but then it solidifies into a person, black hair askew and dangling, bare feet smeared with blood. 

It’s only as he steps closer that Sanemi recognizes the second sword Genya has slotted alongside his own at his belt, a corner of familiar green and white yagasuri patterned fabric peeking out of the top of the pack he's carrying against his front. 

Before he can accost his brother and demand answers as to why the fuck he’s carrying an unconscious Reimei and why in the hell she’s dressed like that, Shinobu appears from a nearby doorway, looking slightly haggard. She and Genya converse for a moment in low voices before she points down the hall, away from Sanemi. Genya nods, turning on his heel and disappearing before Sanemi can stop him, taking Reimei with him. 

Shinobu’s eyes find Sanemi’s and an odd expression crosses her face before it once more smoothes over into her usual cheerful exterior. 

“Shinazugawa-san, what can I do for you?” She asks. 

“What’s going on?” It comes out perhaps more like a demand than it should, if the pinching of her mouth is any indication, but Sanemi’s worry is partially blocking his common sense. 

“Uzui-san’s group has returned from Yoshiwara. They’ve eliminated the Upper Moon Six’s, but most of the group is injured, some worse than others.” She explains. 

“Upper…” Sanemi almost swallows his tongue, realization settling heavy in his gut. 

“Reimei. Is Reimei…” Because she’d clearly been entirely unresponsive, slung across Genya’s back like a sack of rice, and the blood…

“Kumeno-san will be fine. None of the blood you saw was hers, she is simply suffering exhaustion from pushing herself too hard.” Shinobu says soothingly. Sanemi still isn’t entirely convinced, turning to look down the hall the way Genya had disappeared. The Insect Pillar, apparently, can read him like an open book, because her face softens. 

“Kumeno-san is in good hands. Genya-san knows what he’s doing.” She says, reassuring. Sanemi glances at her, still uncertain, but she’s already turning away from him. 

“I must return to my patients. If you’ll excuse me.” 

And then she’s gone, leaving Sanemi standing alone in the empty hallway, a hollow feeling settling in the pit of his stomach.

This demon is fast and Genya is certainly not on the same level as his Sensei when it comes to speed. 

He laments on that fact for a moment even as he skids around a corner, determined to keep the fleeing demon in his sights, because Reimei would have easily been able to overtake it with her speed. Never mind the fact that Genya is just struggling to keep up, but he needs to cut off the demon’s route of escape before it makes it back to the more populated areas of town and finds someone to make a meal of. 

Suddenly, up ahead of them, there’s a shift of movement and a figure steps into a pool of light spilling from a street lamp overhead. A pretty face turns towards them, wide eyes surprised, and the demon lunges, snarling, no doubt expecting an easy meal. 

What he gets is Reimei’s sword slicing through his abdomen. With a terrible, wet thump the two halves of his body hit the ground, blood exploding across the pavement in a pattern that is both grotesque and mesmerizing. It glints wetly under the street light, the puddle spreading as Reimei’s fingers wrap around the demon’s throat and she lifts his torso from the ground to dangle in the air. He wheezes, fighting for a proper breath, but manages to gulp out a few words. 

“...please, mercy…” His legs twitch even as they start to disintegrate, the flesh at the end of his torso slow to start mending. Reimei’s face remains impassive, but her eyes narrow. 

“Mercy?” She asks, voice deceptively light, though Genya can see the muscles ticking in her jaw.

“Did you show mercy to the thirteen preteen boys that you’ve eaten in this town? Did you show them mercy as you hunted them through the streets like animals? Did you show them mercy when they begged you to let them go? Funny, how you only know the meaning of the word when it’s your life on the line.” Her tone has deepened, tapering off into a growl by the end and Genya can’t help but shiver at the barely contained fury that is trapped in every inch of his teacher’s body, making her quiver with rage as she lifts the demon’s dismembered body a little higher. 

“Where was your mercy then?” She snarls into his face. 

“You humans are such hypocrites!” The demon suddenly yells, his hands coming up to clasp at Reimei’s arm, though he is completely ineffective in getting her to release her grip on him. His body has regenerated down to his knees. 

“You eat animals because you have to. Well, we have to eat, too! It just the natural order of things, predators and prey!” He snaps, digging his claws deeper into Reimei’s wrist, blood seeping from the cuts to slide down her arm. 

She doesn't even flinch but, at her back, Genya lets out a warning growl, the sight of his Sensei’s blood making his own claws lengthen and itch. The demon’s eyes go wide as he stares up at the tall boy in surprise, something like genuine fear flickering to life in his eyes. 

“You’re exactly right.” Reimei’s placid, almost conversational tone makes the demon jump, his eyes snapping to hers just in time to watch them bleed red. Her lips peel back as she smiles, revealing a mouth full of razor sharp teeth. 

“Humans eat the flesh of livestock. Demons eat the flesh of humans. Just as you said, everything in this world has a predator that preys upon it.” She tilts her head, regarding the now shaking demon held in her grasp with dispassionate eyes. 

“What made you think that there wasn’t something out there that preyed on demons?” 

Her captive has no chance to answer as she plunges her free hand into his chest, punching straight past the bones of his rib cage to wrap her claws around his heart. It is removed from his body slowly, tendons and muscle ripping as the organ is drawn out, finally coming free with a wet, tearing snap

The demon screams in agony, voice quickly snuffed out as Reimei squeezes her hand around his throat, restricting his vocal chords. She holds him up as she devours his heart, his torso jerking as Genya takes his share. 

Another few moments and nichirin steel is deployed again, the remains of the demon falling as ash to mix with the blood staining the pavement. 

Genya and Reimei stand over the scene for a few more moments, until finally Reimei lets out a heavy sigh and reaches up to run a hand over her hair, smoothing back a few flyaway strands. 

“I apologize for all of this, Genya-kun.” She says, looking away guiltily. 

Genya turns to her, thinking she's referring to everything that’s happened over the last week. 

The two of them have been to four different towns in twice as many days, each with a quickly confirmed kill. Genya has noticed over that time that his Sensei seems hungrier, less patient with their targets, and he wonders if it doesn’t have to do with how far she’d pushed herself in Yoshiwara. That perhaps this binge of demons is her gorging herself to get back up to full strength. 

But he doesn’t say anything about that, instead smiling as he falls into step with her as they head back towards the Inn where they're staying. 

“There’s nothing to apologize for, Reimei-Sensei.” He says, reassuring. Her green eyes slide to him and she tilts her head in the way she does when she’s thinking about something, chewing on her bottom lip. 

“Well, there might be.” She says under her breath, almost too softly for him to catch. 

“Sensei?” He prods gently and she sighs again, shoulder drawing up as if she’s steeling herself for something. 

“You are aware of Uzui’s retirement, yes?” She asks. Genya blinks and nods. 

It’s hard not to know, what with how much larger than life the man is. Wherever he goes, pandemonium seems to follow, and so it had been common knowledge within a matter of hours of their return that Uzui would be retiring from active duty, the man himself nearly shouting it at everyone who came within a ten foot radius of him. 

“With him and Rengoku both retiring within such a short time of each other, the Hashira are suddenly down to only seven members, which puts the Corps at a distinct disadvantage. Not that we weren’t to begin with, but unlike normal Corps members, Hashira are expected to oversee not just their own districts but also their own people. With the loss of the Sound and Flame Pillars, a great deal of territory and rank-and-file Demon Slayers are without supervision.” Reimei explains. 

Genya remains silent, because all of this isn’t anything new to him, but he’s curious where his teacher is going with this conversation, especially when she sighs yet again. Her green eyes find him, steady and serious, and he feels his spine straighten almost automatically under the weight of her gaze. 

“Ubuyashiki-sama has asked me to fill one of the empty Pillar positions.” She says, sounding for all the world like she expects him to take this news poorly. To Genya, however, it is the exact opposite of a problem. 

“That’s great, Sensei!” He exclaims, face splitting into a wide grin in his excitement. She blinks up at him, obviously surprised by his reaction. 

“That means that the Master has acknowledged your strength!” Genya can’t help but beam down at his Teacher, because if the Master of the Demon Slayer Corps is acknowledging his Sensei’s strength, then that means that others will, as well. If they acknowledge her strength, then that will offer her some protection in the event that her secret is exposed.

Reimei’s face softens into a smile, her head tilting in a slight nod of acknowledgement. 

“Thank you for that, Genya-kun. But I think you’re missing my point.” She says gently. He blinks. 

“Which is?” 

“If I became a Pillar, as my only student, you would automatically become my Tsugoku.” She explains. Genya stills, not understanding, and then he straightens self-consciously. Of course, there would no doubt be a great many members of the Corps who would frown at a Hashira having a Tsugoku who can't even use a breathing technique.

“Oh.” He mumbles, head drooping. Reimei’s smile is kind, no hint of mockery to be seen. 

“I’m not saying I wouldn’t be honored to have you as my Tsugoku, Genya-kun. You have made me immensely proud as my student, rest assured of that. But being a Tsugoku comes with responsibilities that simply being a student to a Kinoe does not. You have enjoyed a great deal of freedom, we both have, and if I accept this position then we will lose some of that.” Here she looks away from him briefly, eyes flickering towards the horizon where the sky is just starting to pale. 

“That is why I will only accept the offer if you approve it.” She says firmly, eyes once more finding his. 

Genya very nearly trips over empty air, her words leaving him standing speechless, his mouth partially hanging open. 

Me? Sensei, you can’t be serious. You should decide.” He insists. She shakes her head. 

“This decision doesn’t just affect me, Genya-kun. That’s why I want you to make the choice. Because, while I would be content with either outcome, you might not.” She explains. 

Genya swallows thickly, looking down at his feet as he collects his thoughts. 

“I...When I first started, all I could think about was reaching the Pillars to be closer to my brother.” He says softly, haltingly. And that is still partially true, because whenever Genya thinks of Sanemi his heart hurts with the weight of his regret and longing. He still wants to apologize to his brother, to stand beside him and protect him to the best of his abilities so that, one day, Sanemi may be able to live happily.

“But, since you took me in, I’ve learned a lot and...and I have people I want to protect, now.” He thinks of his brother, of Tanjiro and Nezuko, even of Zenitsu and Inosuke. But most of all he thinks of his Sensei, who has taught him so much and protected him through it all. She's shown him the value of being selfless, of putting others before oneself not for the sake of glory, but for love. He knows without a shadow of a doubt that she would give her life for his, and he feels the same.

Determined, Genya lifts his head, meeting his teacher’s gaze head on. 

“When do we start?” He asks. Reimei seems to search his eyes for a moment, looking for something, and then her face breaks out into a warm smile, her eyes crinkling up at the corners. 

“Soon. I’ll inform Ubuyashiki-sama while you’re at the swordsmith’s village. The appointment ceremony should be sometime after you get back.” She says, turning to start walking again. 

“Huh? Why am I going to the swordsmith's village?” Genya asks, once more falling into step beside her. 

“Because I had to have two new guns commissioned after someone broke theirs during the Yoshiwara incident.” She says, tone light and teasing, but that doesn’t stop Genya’s ears from going red at the tips. 

“It was an accident! Tanjiro was in danger!” He defends. 

Reimei laughs, the sound high and bright and clear in the early predawn quiet, and Genya can’t help but smile, too. 

Maybe being a Tsugoku will be hard. It will certainly be more work. But Genya will be content so long as he gets to stay by his Sensei’s side.

Chapter Text

“Please have a seat, Kumeno-sama.” Reimei tries not to flinch at the honorific, considering it comes from Ubuyashiki Amane, but it’s a close call. She is aware of seven sets of eyes on her as she moves to sit carefully beside the Master’s wife, but she ignores them in favor of keeping her eyes on her hands, clasped neatly in her lap. 

Now is not the time to become distracted, even as she feels the weight of one particular stare more than the others. 

“Kagaya-sama has nominated Kumeno-sama to the position of Hashira, which she has accepted. From this day on, she will join your ranks as a Pillar of the Demon Slayer Corps.” Amane says formally. 

There is the barest pause as the seven Hashira seated across from her place their hands on the floor and bow, but Reimei is hyper aware of every rustle of fabric, every measured breath, every hesitation. 

“We understand. Kumeno Reimei, we welcome you to the ranks of the Hashira.” Himejima's bow is the deepest, his scarred forehead almost touching the floor, and there seems to be genuine emotion in his tone. Reimei steels herself and returns the bow, touching her fingertips together and leaning forward at the proper angle the way her father had taught her. 

“I look forward to working with you.” She says, keeping her voice soft, tone as even as she can make it. As she straightens, Amane begins to speak once more. 

“As you all may or may not be aware, Kumeno-sama is the daughter of the former Wind Pillar, Kumeno Takashi. While it is not expressly forbidden by Corps rules, there have never been two Hashira of the same breathing style who were active at the same time. So, while Shinazugawa-sama and Kumeno-sama will both have the title of ‘Wind Hashira’, Uzui-sama has graciously offered the Sound Estate for Kumeno-sama’s use.” She explains. 

There’s a slight shift among the Pillars at the news, but no one speaks out. 

“Furthermore, Kumeno-sama has named her only student, Shinazugawa Genya, as her Tsugoku. Kagaya-sama has accepted his nomination.” Reimei doesn’t have to be looking at Sanemi to know he’s flinched, the hiss of his next exhale like grit running over the skin of her neck. 

She keeps her face down through the rest of the meeting, only half aware of Amane’s explanation of Nezuko’s conquering of the sun and what it means for the coming battles, about the marks, how they appear and why, and about the Pillar training that is going to commence to see if others can develop the marks. 

In fact, it isn’t until Amane turns to address her again that she becomes aware of just how tight her shoulders are, her spine starting to ache with how tense she is. 

Because knowing what’s coming isn’t making the prospect of facing it any easier. 

Reimei knows, without a shadow of a doubt, that all of the Pillars sitting across from her pose a serious threat. Perhaps, in a one on one fight against someone like Himejima or Sanemi she could escape with her superior speed, but facing someone like Mitsuri or Shinobu would have dire consequences, even if she did manage to flee with her life. 

She’s survived for this long by being beneath notice, despite her unusual coloring. Therefore it doesn’t sit well with her to throw her deepest secret at the feet of people who could easily turn against her, but Ubuyashiki believes it is for the best that the other Hashira know

Reimei doesn’t really agree, but Ubuyashiki had promised nothing bad would come of it. 

She just hopes he’s right. 

“Finally, Kagaya-sama would like to bring something to light. As you are all aware from the meeting following the Mount Satagumo incident, Shinazugawa Genya is capable of consuming demons in order to temporarily attain some of their strengths. Kumeno-sama was assigned as his teacher because she shares a similar ability. For the past four years Kumeno-sama has, along with her student, been hunting down demons that are classed as Demon Moon candidates. That is, demons that are strong enough that, if an opening in the 12 Kizuki should open up, they would be moved into that vacant position. She has been doing so in order to obtain some of their strengths and abilities in anticipation of the coming battles.” Amane explains. Reimei once more feels the weight of curious gazes, several heads coming up in interest. 

“I thought that the strength brought on by eating demons was only temporary?” Giyuu is the one to finally break the tense silence. 

“That is correct. However, while Shinazugawa Genya can only use a demon’s strength for a short period of time, Kumeno-sama can tap into their power days, weeks, or sometimes months after she has consumed them. Using said abilities shortens their usage, but the fact remains that her baseline strength, speed, and endurance are elevated. She has also gained a marginal healing factor.” 

There’s a murmur, then, the faintest shift of unease, and Reimei has to tamp down on the urge to bolt, fisting her hands tight enough that her nails dig painfully into the meat of her palms. 

“Doesn’t seem like such a unique ability, if there’s two Demon Slayers who can do it. If it wasn’t such a disgusting practice, I’d suggest we all try it.” Obanai says, voice just this side of snide. Amane’s eyes flick to him, then to Shinobu. 

“It might be better to describe Shinazugawa-kun and Kumeno-san's abilities as abnormal, because eating demons is not something that ordinary people can do. The average person, once they have consumed a demon, will immediately go mad and die.” The Insect Pillar explains with a chilling smile. 

“Before he learned of Shinazugawa Genya, Kagaya-sama believed that Kumeno-sama was wholly unique and that there would never be another like her. In reality, while the two have similar abilities, there are marked differences.” Amane continues once Shinobu has finished. 

“What are those?” Mitsuri asks, curious. 

Reimei can feel Amane’s gaze, like a physical weight, and finally lifts her head. Her nails have broken skin, but she keeps her bloody hands hidden in the sleeves of her haori, making sure to keep her eyes normal and her teeth blunt. 

“Because, unlike Genya-kun, I need to consume demons as a regular part of my diet. Going too long without causes weakness, immense fatigue, and terrible bouts of sickness. Kanae-san speculated, and Shinobu agrees with her hypothesis, that if I were to quit eating demons entirely I would slip into a coma and my body would stop functioning. In other words, I would die.” She explains. 

There is a pregnant pause at that, a startled kind of undertone to the silence that nearly makes Reimei fidget. She is determined to appear as non-threatening as possible. 

“So, you’re like a demon...for demons?” Mitsuri is the one to break the silence, and at her words the other Hashira seem to tense up even more. Reimei hides a nervous swallow with a nod. 

“In a sense. I can go about a month or so between needing to eat a demon, and I can extend that time a little thanks to Shinobu.” She says. All eyes swivel to the Insect Pillar and she inclines her head. 

“My sister developed a medicine, derived from the blood of demons, that I supply to both Kumeno-san and Shinazugawa-kun. While not nearly as potent as the real thing, we have found it sufficient for short term usage.” She explains. 

Another pause falls over them as the Hashira take in this new information, and then Iguro’s hands fall to the sheath of his sword. Reimei’s eyes immediately snap to him, every muscle tensed and ready as her body goes on high alert, prepared to either dodge or defend. 

“Give us one good reason we should let you live.” The Snake Hashira says, and though his voice is even his eyes glint dangerously. 

“Iguro-sama.” Amane’s voice is a warning, but he shakes his head. 

“This all sounds far too much like the Corps has taken in and is harboring a new type of demon. You say they only eat demons, but it’s too dangerous for anyone else to try. How can you be sure? What happens if they eat too much? Will they lose themselves one day? Will they turn on humans then?” His eyes narrow as they focus in on Reimei, his snake hissing as it tucks itself farther into his collar in preparation to strike. 

A tense moment passes, drawn out like a string until it vibrates with the tension in the room. Reimei is fighting the tremors in her hands, every fiber of her being screaming that she flee or fight, even as she keeps her breathing measured and even. She knows that she must not give in to temptation and pull up the power roiling like lava in her gut, as her instincts are demanding she do. 

Because if she fails here, then there is a very real possibility that Genya will be in danger. 

“Kumeno-sama is the reason Kyojuro-sama is still alive.” 

Amane’s voice cuts through the silence like a knife, the tension snapping and disintegrating like a popped bubble. Iguro blinks, his eyes sliding from Reimei to the Master's wife. All of the Hashira, in fact, turn as one to look at her, and she offers them a small, formal bow. 

“When he was mortally wounded by Upper Moon Three, it was only thanks to an infusion of Kumeno-sama’s blood that he was able to be saved.” She continues. 

“How?” Shinobu's voice is sharp, eyes intense as they zero in on Reimei, who hesitates for the briefest moment. 

“My healing factor can be temporarily passed to others.” She admits reluctantly. The stares she’s receiving now are different from before, tinged with awe and a little bit of concern, but the hostility from earlier is gone. 

“Why would you do that?” Iguro looks stunned, astonishment reflected clearly in his eyes. Reimei blinks, feeling her shoulders relax as the tension bleeds from the room. 

“Because Genya asked me to.”

For Reimei it’s like everything is moving in slow motion. 

She is vaguely aware of the Corps members strewn around the yard, shaking with fear, but they are little more than fuzzy blobs of color at the peripheral of her vision. Only a few things are in crystal clear focus, like the tears in the rice paper screen that is lying broken amidst the stirred up gravel, the creasing around Sanemi’s nose as he snarls down at Tanjiro. 

The bright red blood trickling down Genya’s cheek. 

Understanding brings with it a quaking rage, the quiet numbness of the moment suddenly burnt away, swept under by a tide of anger. It is the kind that prickles at her skin, the kind that makes her teeth itch and her throat click as she swallows, and she gladly lets it swallow her up. 

For Sanemi, instead of his punch landing squarely in Tanjiro’s stomach like he'd planned, his entire body moves without his conscious input, instinct making him twist away to dodge an unseen threat. It’s only as he lands that he hears the whistling of a gale force wind, the sound having only become audible a full second after Reimei’s sword edge had cut through the space where he had just stood. 

His breath falters in his lungs, shock making his muscles seize as he stares up at the wall that surrounds the Wind Estate.

Or, at least, what's left of it.

It looks as if a giant had taken a massive cleaver and swung it straight through the timbers, the gash long enough to span almost the entire length of the yard. A moment drags out where nothing happens until gravity seems to remember that it has a fucking job to do and wood begins the creak in protest, the cracking and splintering sounds of planks and solid posts splitting finally beginning to echo across the dead silent training ground.

Sanemi’s heart is thundering in his chest as he turns slowly and he feels his throat close up when his gaze meets what he knows are demon-red eyes. They’re narrowed in anger, mere slits in Reimei’s pale face, her nose scrunched up and her lips peeled back to reveal sharpened teeth in an ugly snarl.

She doesn't wait for him, doesn't give him time to dive for his sword, her shape flickering as she moves with a speed that makes Sanemi's eyes water. For several tense, terrifying minutes they simply exchange blows, Sanemi having managed to snag the hilt of his sword while dodging a particularly vicious swing. The rest of the training yard is deathly silent, their audience watching in stunned awe as the two Hashira dance around each other.

Reimei spins away from a downward swing, bringing her sword around in a whistling arc to slam against Sanemi's, the two green blades sparking as their edges grind together.

"...are you..." Sanemi only catches the tail end of her growl, too busy trying to keep his shaking arms braced against her enhanced strength.

"How dare you?!" Reimei's face is twisted with her snarl, taking a step forward despite Sanemi's best efforts, driving him back from the single point of contact between their blades. Sanemi decides to retreat, leaping away to put distance between them. Reimei doesn't immediately follow, her fangs grinding together as her jaw ticks.

"What's wrong with you, that you'd attack your own brother? Have you no shame, no sympathy?" Her voice is shaking, her anger clear to all those gathered. Sanemi bares his own teeth.

"You idiots don't get it!" He shouts, face twisting in frustration.

"Neither one of you morons understands! You shouldn't fucking be here!" He's seething, breath hissing as he tries to force his thundering heart to calm, despite the adrenaline running like ice through his veins and the fear clouding his mind. Across from him, Reimei is watching him with an appraising expression, her eyes having narrowed at his words.

"You both insist on getting underfoot. I don't need you sticking your nose into my business and I certainly don't need such a useless little brother. You should just get out of my sight!"

A long, tense silence falls. It feels as if the world is holding its breath, waiting on tender hooks for what comes next. Reimei's head has lowered and Sanemi's breathing is labored, but it stalls completely at her next words.

"Give him back."

Sanemi's eyes widen as Reimei lifts her head. Her eyes are back to a normal, human white, but they're wet with tears, anger and grief causing her eyebrows to furrow and her mouth to twist.

" say you don't need your brother, so give mine back!" Reimei's voice rises until she's shouting, her voice cracking brokenly on the last word.

Sanemi feels like he's been gutted, her words flaying him open to reveal wounds he'd tucked away and tried, unsuccessfully, to forget. Reimei takes a heaving breath, her hands shaking around the hilt of her sword, the point having fallen to touch the ground.

"Masachika-nii...he loved you like a brother, he gave his life for you, so you could live. He did that for you. And instead of respecting that, instead of honoring his sacrifice, you trample on his memory." She spits the words, each syllable out of her mouth like another knife between Sanemi's ribs. Reimei shakes her head, as if trying to clear it, before she straightens, her expression fierce.

"Do you even hear yourself? 'I don't have a brother.' Do you have any idea what I wouldn't give to have my brother alive? You're lucky enough to have that, but you don't appreciate it." Her face falls, though her eyes are still too wide, glassy with tears. She takes another shaky breath, steadier this time, before sheathing her sword in one smooth motion. She turns her back on Sanemi and her final words cut him to the quick.

"My brother's life was wasted on you."

The only sound is the crunch of gravel under Reimei's feet as she walks out of the yard, her shoulders stiff and her back ramrod straight. No one moves, the Corps members too stunned by what they've just witnessed to even dare drawing attention to themselves.

Sanemi can hardly breathe, barely registering when Genya casts him a quick glance before he hurries after his teacher. It feels like his ribs are too small, his chest aching as his heart trips and stutters, his gut roiling with an acidic burning sensation not unlike bile.

Reimei's words echo in his head, rattling around inside his skull, more effective than any blade.

She could not have cast him any lower.

Chapter Text

We may shine, we may shatter,
We may be picking up the pieces here on after,
We are fragile, we are human,
We are shaped by the light we let through us,
We break fast, cause we are glass.

Glass, Thompson Square

Genya slides the door closed behind him, mind whirling. 

In all the years he’s been with her, he has never seen his Sensei like this. Her eyes are dull and listless, face frighteningly blank, her voice little more than a whisper. She seems brittle, like a piece of pottery that has spent too long in the kiln. A wrong step or a harsh word seems enough to shatter her, and it frightens Genya. 

Unlike a physical threat, he cannot shield her from this. He cannot bandage this wound, there exists no salve he can apply to ease her pain, no amount of stitches that can be used to close the hole. 

Because a heart is not something so easily mended. 

He knows this, can feel it in the answering ache in his own chest, like a sympathetic drumbeat under the skin of his ribs. 

But Genya is stubborn, just like his older brother. His formative years may have been spent beside Sanemi, but he’s grown up under the tutelage of his teacher. 

With that thought, Genya’s head comes up, shoulders squaring as he turns to walk purposefully down the hallway. 

He is Shinazugawa Genya, Tsugoku of Kumeno Reimei, Wind Hashira of the Demon Slayer Corps. 

He is going to make this right.

The Wind Estate is still a mess, because though the debris has been cleared away by the Kakushi, there’s still the glaringly giant hole where the wall surrounding the training grounds once stood. 

Genya barely spares it a glance, gravel crunching under his boots as he walks across the yard, headed for the back of the property. 

He finds Sanemi sitting on the edge of the engawa, bare feet dangling, staring blankly off into space. 

He doesn’t so much as twitch as Genya approaches, or when he hauls himself up to sit beside his brother, his longer legs meaning the soles of his boots rest firmly in the gravel. 

They sit in silence for several minutes, the only sounds the calls of birds at the edge of the garden, the rustle of the trees in the wind. 

Surprisingly, it’s Sanemi who speaks first. 

“It was my fault.” 

Genya doesn’t speak, doesn’t turn to look at his brother, though he can see the other’s shoulders hunch in his peripheral, an uneven breath leaving him in a shudder. 

“I slipped up, against Lower Moon One. A rookie mistake, stupid, but Masachika…” He trails off, head drooping until his back is bowed, the tips of his hair brushing his knees, right hand twisted in the fabric of his shirt, right over his heart. 

“I don’t think Masachika even knew what he was doing until he’d already shielded me. He got hit, but it gave me an opening, just enough time, but by then it was too late for him.” Sanemi’s breathing is labored, ragged, but still Genya keeps his eyes forward, waiting. 

“He bled out in my arms, the fucker. Told me...told me to take care of Rei, of Takashi-san, that he was so proud of me.” Sanemi falters, breath hitching, but continues. 

“After I just...I couldn’t face either of them. The idea of explaining myself to Takashi-san was painful enough, but just thinking about Rei’s reaction hurt. So I just...didn’t. I thought, eventually, they’d forget me. Takashi-san would take on other students and Rei...Rei would grow old up on that mountain, safe from the rest of the world.” Sanemi shifts a little and Genya can feel the weight of his brother’s eyes on him. 

“You were supposed to forget me, too.” 

That makes Genya start a little, head turning so he can look at Sanemi properly. His brother looks miserable, face drawn and mouth a tight, grim line. 

“You were supposed to grow up outside of all this.” Sanemi waves a hand vaguely through the air. 

"Settle down, get married, have a couple of kids, give them the kind of life we couldn’t provide for our younger brothers and sisters.” Genya’s throat is closing up, the grief in his chest rising up to choke him at the resigned look on his older brothers face. 


“I killed our mother.” Sanemi cuts him off and Genya’s hands tighten on his knees, startled. 

“I killed our mother to protect you. That means I would never have let a demon near you, or your family. You were supposed to be happy.” Sanemi trails off, eyes lost in the distance, not really seeing Genya. 

A long moment of silence falls between them again, tense, wavering.

“I am happy.” Sanemi’s eyes snap into focus, zeroing in on Genya, who tilts his head on a shrug. 

“I’m happy when I’m with Reimei-Sensei. I’m happy when I’m with Tanjiro, and Nezuko, Inosuke, and Zenitsu. I’m happy that I’ve gotten stronger, that I can protect the people who are precious to me.” He trails off, staring out at the garden, thinking. 

“The life you wanted for me, I don’t think I could have been happy with that. Knowing what was out there, lurking in the shadows, always looking over my shoulder, wondering and worrying about you. I would have been miserable.” Genya turns to lock eyes with his brother, who has fallen uncharacteristcally silent. 

“I’m not happy when the people I love are suffering. All these years, I’ve wanted to apologize to you. I should never have called you a murderer, that was wrong. I was afraid, grieving, but that doesn’t excuse my actions.” He glances away, scuffing the toes of his boots in the gravel. 

“Sensei says that human beings are like time. Once they’re gone, there’s no way to bring them back, so we have to cherish the people we love while we can, because once they’re gone, that’s it.” Genya’s eyes find Sanemi’s, wide and still beside him. 

“You can’t do this alone, Nii-chan, and neither me or Reimei-Sensei are going anywhere.”

They stare at each other for several long, silent moments before the first crack appears, Sanemi’s breath hitching as he blinks frantically. 

“Idiots, both of you.” He snaps, but there’s no venom in his voice. Genya hums. 

“We’ve been called worse.” He says with a shrug. Sanemi doesn’t laugh, but the breathy snort he lets out is close enough. His expression sobers a moment later, eyes turning serious. 

“I thought you’d be angry.” He says, voice uncharacteristically quiet. “That you would hate me.” 

Genya doesn’t hesitate, leaning over to loop one arm around his brothers shoulders and wow, he’d never thought about his brother as small before, but his arm easily wraps all the way around the man and then some. 

“I could never hate you, Nii-chan. But because I know you won’t believe me, for whatever it is you think you’ve done, I forgive you.” Sanemi breathing is ragged, a suspicious hitch to it that Genya doesn’t comment on. Slowly, one scarred hand moves to fist in the back of Genya’s shirt, and if Sanemi’s fingers shake then neither of them says anything. 

They fall silent again, simply leaning against each other, all the years of pain and suffering like a dull throbbing at the back of Genya’s head. Loathe as he is to break this peace, he knows he has one more heart to mend. Slowly, he draws back, making sure that Sanemi is actually looking at him before he speaks. 

“You need to talk to Reimei-Sensei, Nii-chan.”

The Sound Estate is quite pretty, all things considered, with a small but neatly kept garden. Upon their arrival, both Genya and Reimei had been surprised that the entire place wasn’t entirely encrusted in gems and brightly colored fabric, so it’s obvious that Uzui’s wives had been in charge of decorating. 

Reimei is sitting in the tea room, the outer doors pushed open so that she can look out onto the garden. There’s a stream somewhere, out of sight, because she can hear the bubble of water below the chirp of birds and the creaking of the crickets. 

But Reimei isn’t really watching the gardens, the play of light over branches or the way the small house birds flit amidst the foliage, singing as they go. 

No, she’s thinking about earlier, about the bright shine of blood and dull white hair, scarred skin and fearful, dark eyes. 

In truth, she’d let her anger get the best of her, her hurt clouding her judgement, but she just can’t understand Sanemi’s reasoning. His stance, his words, his whole demeanor towards his brother irks and confuses her, their own history notwithstanding. 

So, perhaps, she’d let things get out of hand. She feels justified, if a little bit guilty for the damage they’d caused. 

She sighs, running a hand through her hair absently. She’d taken it down, something to do with her hands while she got lost in thought, but her fingers still when there’s a soft tap at the door. 

Genya slides the door open a moment later, expression more relaxed than she’s seen in a long time, though there’s something uncertain in his eyes. 

“What is it?” She tries to put some inflection into her voice, some semblance of life, but it’s difficult. Her heart still hurts too much. Genya’s eyes flicker. 

“There’s someone here to see you, Sensei.” He answers. Reimei sighs, shoulders slumping. 

“I’m not really in the right frame of mind to see anyone right now, Genya-kun.” She says truthfully. Genya nods. 

“I know.” His voice is soft, understanding, but laced with determination, even as Reimei’s eyes snap to him, confused. He pushes the door open a little farther, revealing the last person Reimei expected to voluntarily pay her a visit. 

She’s so stunned that she doesn’t move when he stands, crossing the room silently on socked feet, before dropping back to the floor before her in a deep bow, his forehead touching the tatami

She’s so stunned that she barely registers when he starts talking, voice muffled because his face is still pressed to the floor, apologies falling from his lips like a litany. About how he’s sorry about Masachika, that he shouldn’t have taken him for granted or some other nonsense, as if Masachika himself hadn’t loved Sanemi like the brother they’d lost. How he’s sorry he didn’t make up with Genya sooner. How he’s sorry he didn’t work harder. How he’s sorry he wasn’t strong enough to protect her and Genya, that he’d failed in his mission, and really, she’s beginning to wonder if Sanemi isn’t thick in the head. Maybe she is, too, if the tears trailing down her face are any indication. 

“You...idiot…” Her voice cuts him off mid-word and he starts, head lifting so he can meet her teary eyes in surprise. 

“I was never angry at you over Masachika-nii’s death. We, father and I, we knew he’d died doing what he thought was right. But I...I wasn’t supposed to lose you too, not when you where still alive.” She takes a shaky breath, voice wavering as she wipes furiously at her face with her sleeve. 

It’s no use, though, the floodgates refusing to close. She feels Sanemi’s arms winding around her, solid, tangible, and she leans into him just as easily as she did years before, her hands fisting in his jacket as she buries her face in his shoulder and sobs. His fingers are gentle as they run through her hair, soft apologies on his breath as he holds her through it. 

Genya, for his part, slides the door to the tea room closed as quietly as he can, giving his brother and teacher some privacy. 

This is by no means the end of it, not nearly enough to close the wounds they share. 

But it’s a start.