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Sex, Science, and True Love: A Rigid Analysis of the Practical Applications of Dual Cultivation

Chapter Text

The thing was, Wei Wuxian thought, once he’d returned to his room, it wasn’t as though he had forgotten that the reason for his research was potential dual cultivation with Lan Zhan. It was just that for the sake of maintaining his own sanity, he had carefully focused exclusively on the dual cultivation aspect and relegated with Lan Zhan to a distant, dark corner in his mind. 

Which had worked until this happened. Now, instead of picturing faceless, impersonal bodies writhing together in the Soaring Phoenix position as described in Journey to the Vermillion Cave, it was him and Lan Zhan — fingers entwined, hair in disarray, lips parted and panting as they drove each other towards— 

He stood up, face aflame. The heat in the room was stifling. 

A long walk in the damp morning air helped cool his blood. He procured a jar of Qinghe’s best wine from the storerooms, found an unoccupied rooftop, and drank until his thoughts no longer thrashed about in his head like wind-blown leaves. 

Perhaps he was overthinking things. Of course he found Lan Zhan appealing; it would be stranger if he didn’t. Lan Zhan was, after all, a flawless pearl of a gentleman: master of all six arts, one of the best cultivators of their generation, and so beautiful that even the legendary Pan An and Lanling Wang were but dull sparrows to his regal crane. It was simply a matter of Wei Wuxian having eyes and good taste. 

Admittedly, his recognition of Lan Zhan’s appeal had not previously manifested in the form of arousal, but it was also the first time in months, since before the destruction of Lotus Pier, that he’d felt well. He’d read in Wen Qing’s medical texts that sometimes the body could confuse cessation of pain with pleasure. Surely this was what had happened in Lan Zhan’s room. 

Besides, there were more important things to consider. From a purely objective and scientific standpoint, the fact that their test had worked at all was fascinating. Even if Wei Wuxian’s qi wasn’t now irrevocably tainted with resentful energy (which Lan Zhan should have found repulsive; why hadn’t he?), spiritual energy transfers in general tended to be inefficient and even unpleasant if the recipient’s qi fought the foreign intrusion. Wei Wuxian had seldom needed one since he’d developed his golden core, and it had always felt like forcing his feet into ill-fitting shoes. 

But his qi had welcomed Lan Zhan’s spiritual energy, as eager as parched earth for rain. His hands still tingled with the memory of that liquid light, tiny firefly sparks where Lan Zhan's fingers had touched. Was this what the dual cultivation stories had meant by affinity of qi? If so, he could see why it would be so important. 

And so, uh… nice. Perhaps the descriptions of overwhelming pleasure and heartrending passion were not entirely unrealistic exaggerations. 

Heat prickled in his cheeks. Lan Zhan had been blushing too, at the end. 

Clearly another long walk was in order, possibly to a cold spring this time, or whatever the Unclean Realm had that was closest.

“Never thought I’d ever miss the Cloud Recesses,” Wei Wuxian muttered, and leapt from the rooftop. 

The next day, Nie Mingjue announced the battle plan. The allied cultivators would split into a vanguard and a main force. The vanguard would clear a path through Wen-occupied lands to an outpost on the north bank of the Yellow River, liberating the smaller sects and recruiting any willing fighters to join them in forging ahead and establishing a foothold on the opposite bank. The main force would escort the supply train and noncombatants to that same outpost. From there, they would scout the best approach into Nightless City.

With a departure set, their days in Qinghe turned into a mad scramble of activity. Everything had to be recounted, people who fell ill had to be replaced, damaged equipment had to be repaired. Wei Wuxian, who’d spent his childhood lazing amidst calm water and sun-warmed lotuses, marvelled at the chaos and efficiency of it all. 

The last night before their departure, Jiang Cheng found him in one of the caves that dotted the mountain surrounding the Unclean Realm. Unlike the Cloud Recesses, which was almost eerily pure, there was no shortage of resentful energy here. Wei Wuxian suspected that it had something to do with the Nie sect style of cultivation, but even he wasn’t so churlish as to ask. 

He put down Chenqing as Jiang Cheng approached, releasing the spirits he’d summoned to practice his control. “So, what’s happening?”

Jiang Cheng snorted and crossed his arms. “You could always attend the strategy meetings and find out for yourself.”

Wei Wuxian rolled his eyes. “It’s not like I have anything useful to contribute to the conversation anyway. Besides, if I wanted to spend my days getting glared at, I’d go bother Lan Zhan. He’s at least prettier than that peacock and his cousin, what’s-his-name.”

“Jin Zixun,” Jiang Cheng answered, to Wei Wuxian’s dismissive wave. “They wouldn’t glare at you if you’d just carry your sword.”

“And let them win? No way.”

Jiang Cheng heaved a long-suffering sigh and shook his head. “Fine, do what you like, it’s what you’ve always done anyway.” He turned and left, adding, “Jie wanted you to know that she made soup, but I’ll just tell her you’re practising inedia and that I can have your share.”

Wei Wuxian bolted after him. “Jiang Cheng, don’t you dare!” Jiang Cheng walked faster; Wei Wuxian broke into a run. “You brat, where’s the respect for your da-shixiong?”

They bickered their way down the mountain. Jiang Cheng shoved Wei Wuxian into several bushes. Wei Wuxian stripped the leaves off the bushes and shoved them down the back of Jiang Cheng’s collar. 

They found Shijie sitting at the table in her room, with three bowls and a covered pot laid out on the tabletop. She raised her eyebrows as they entered, Wei Wuxian still brushing leaves from his clothes, but rose to ladle steaming soup into one of the bowls. 

“For Sect Leader Jiang,” she said, with delicate pointedness. 

Jiang Cheng flushed scarlet and took it sheepishly. 

She turned to Wei Wuxian next and filled another bowl. “For Jiang sect’s First Disciple.”

“Thank you, Shijie,” Wei Wuxian said, and pouted at her from beneath his lashes until the smile hovering at her lips broke across her face. He grinned, drank a hearty spoonful of soup, and — frowned. 

There were goji berries swimming in the fragrant broth, like tiny goldfish in a pond. Almost as tiny were the pieces of pork, completely dwarfed by considerably larger chunks of lotus root. Wei Wuxian cast a surreptitious glance at Jiang Cheng, whose bowl was just as tragically lacking in meat. Jiang Cheng shrugged back at him. 

A truly horrible thought slid into his mind. “Shijie,” Wei Wuxian said, in tones of most profound betrayal, “did you give all the pork to someone else?”

Shijie laughed. “No, silly boy. Men should eat yin-natured food before a battle to balance their yang energy. It’s good for your qi.”

Wei Wuxian’s breath hitched. He slurped down more soup before she could notice. 

“Besides,” she continued, addressing Jiang Cheng now, “you should both be grateful — the Lan sect men are eating bitter vegetables.”

“That’s what they always eat,” Wei Wuxian muttered, but smiled winningly when she pursed her lips. “If Shijie says it’s good it’s good for me, then I’ll drink all of it!” He finished his soup as diligently as the most obedient disciple, then put on his most pitiful expression and nudged his empty bowl back in her direction. “But Shijie, couldn’t Xianxian have just a little more meat? You see how thin I am.”

“Let him starve, A-jie,” Jiang Cheng said heartlessly, and ducked the swipe Wei Wuxian aimed at his head.

Later, while recovering from his nightly struggle with the Yin Tiger Seal, Wei Wuxian thought about what Shijie had said. He did know about yin-natured food, of course; he had paid attention during his lessons, no matter what everyone used to say. Cultivation was a process of internal alchemy where one nurtured the Three Treasures: jing, the essence of the body; qi, the balance of yin-yang energy that powered all life; and shen, the spirit or the mind. 

Shen was cultivated through meditation. Qi was cultivated through sword training, which created spiritual energy that was then stored in the golden core. Jing could either be nourished by having a clear shen, balanced qi, and an otherwise healthy regimen of diet and exercise; or conserved by refraining from self-pleasure.  

Dual cultivation, however, could apparently create jing. 

He had no illusions about his fate. Without his golden core, he would never be a true cultivator again. When he was hunting Wen Chao, he’d had to anchor his talismans in his own blood, because he couldn’t infuse enough spiritual energy into the cinnabar ink. After he’d been reunited with Suibian, he tried using it once, moving through the familiar forms of Yunmeng Jiang’s sword style. He’d lasted barely half an incense stick’s time before the hilt had fallen from trembling fingers, before he had fallen to his knees in exhaustion. 

Resentful energy was wild and fiendishly difficult to control, but it was all he had. And if dual cultivation really could replenish his jing, keep him healthy even if it couldn’t prolong his life, then… maybe it was worth pursuing, after all. 

He sighed. 

Of course, there was the other issue of the fact that dual cultivation required both yin and yang energy, and neither he nor Lan Zhan was a woman. Even if Wei Wuxian knew a female cultivator whom he would trust enough to engage in this endeavour, he was barely producing enough yang energy to sustain his own qi. 

He really ought to talk to Lan Zhan again. Though considering how their previous two conversations had gone, Wei Wuxian should probably plan for a time when he'd be less prone to saying and doing stupid things.


He didn’t talk to Lan Zhan again. Not for a lack of opportunity — they’d both volunteered to escort the supply train and noncombatants — but leading a large group of people through unfamiliar territory occupied all of their time and attention. Food got wet and spoiled, water got fouled, swords got rained on and rusted. 

At least he didn’t have to deal with the petty squabbles anymore; Shijie had worked her magic on the entire host by the end of the third day, bending even the most mulish to her gentle but implacable will. 

No one attacked them, which was fine — a relief, even — until word came from the vanguard that they weren’t being attacked either. Every minor cultivation sect reported the same story: the Wens had swept through their lands like the receding tide, taking every able-bodied fighter with them. 

The people here believe that the Wens took hostages for ransom, Jiang Cheng wrote. Or that they are the hostages, to force those who were taken to fight for the Wens. Jin Zixuan and I feel that using them as human shields is more likely, though some of the others from our side have already started bragging that the Wens are running away.

Wei Wuxian remembered Wen Chao turning the Wen civilians into puppets when he and Lan Zhan had gone searching for the missing pieces of Yin metal. Grimly, he wondered if they were being led into a trap. 

His fears were confirmed when they reached the encampment. The vanguard had won their foothold on the other side of the Yellow River, but they’d faced a fearsome enemy: Yin metal-controlled puppets, not just hapless villagers this time but actual cultivators. The missing cultivators, who attacked with mindless ferocity and infected anyone they touched. 

Wei Wuxian caught up with Jiang Cheng as the vanguard brought in the last of the infected Jiang sect cultivators. “How many did we lose?”

“Too many,” Jiang Cheng said, mouth tight and tired. “We tried to fly, but…” He held up his arm. A ragged tear slashed through the fabric of his sleeve, exposing a thin sliver of skin.

“Archers,” Wei Wuxian realized.

Jiang Cheng nodded. “We took as many prisoners as we could, without further endangering ourselves. The rest…” He swallowed hard. “We had to kill them so they’d stop attacking. Even when we cut off their arms, some tried to bite.”

Wei Wuxian swept his gaze over the cultivator puppets, pausing when he caught sight of a girl in Jiang sect purple: Li Hong, a third-year disciple. She’d been visiting her grandparents in Yiling when the Wens had attacked. Her two older brothers had fallen along with Lotus Pier.

He cursed, quietly and viciously. “That’s why there weren’t any Wen cultivators on the way here. Why risk his own people when he can make us kill each other?”

Jiang Cheng followed the direction of his gaze, and grimaced. “I know. Look, I need to report in, can you—”

“Go,” Wei Wuxian urged. “I’ll take care of things here.”

When Jiang Cheng found him again, an hour later, Wei Wuxian had isolated the infected cultivators in a tent on the outskirts of the encampment. He’d come up with a suppressing talisman to keep them dormant, and had also chained them to metal spikes driven deep into the ground. 

“What’s the plan?” Wei Wuxian asked, tucking his bloody hands carefully behind his back as Jiang Cheng approached. 

“Zewu-jun, Jin Zixuan, and I will lead a three-pronged assault on Nightless City while Chifeng-zun sneaks in and assassinates Wen Ruohan,” Jiang Cheng said. He looked less strained than he had earlier. “We have a map of Wen sect’s formations. Zewu-jun has someone on the inside.” 

“Who?” Wei Wuxian asked sharply. 

Jiang Cheng shrugged. “He wouldn’t tell us. Apparently the spy’s information is accurate, though.”

Wei Wuxian narrowed his eyes, but decided not to press. He tilted his head at the rows of unconscious cultivators. “What about these people? Lan Zhan says it’ll take at least three months of spiritual energy transfers to heal them.”

“We’ll leave some cultivators here to guard the wounded and protect the noncombatants.”

Probably not the best cultivators, who’d be needed in the attack on Nightless City. If that attack failed, Qishan Wen would descend like a hammer on anyone who was left. 

They couldn’t fail, then. “When do we leave?”

“Tomorrow. We attack Nightless City in seven days.” Jiang Cheng gave him a long, searching look, then added, “We can’t defeat Wen Ruohan unless we can counter his Yin metal.”

Wei Wuxian met his gaze squarely. “I know. I’ll figure it out.”

They left early the next day, in three divisions of Jin sect, Nie sect — led by Lan Xichen in Nie Mingjue’s absence — and a combined force of Jiang and Lan sects. This close to Qishan, the air was perpetually choked with volcanic ash, turning the sky dishwater grey. Jin Zixuan’s gold-clad contingent looked almost jaundiced. Even Lan Zhan’s radiance was slightly dimmed by the unrelenting gloom, though he still looked impeccably handsome. 

The divisions’ paths split shortly after crossing the river. It was a risky tactic, to further reduce their numbers, but the craggy forest that studded the mountains around Nightless City would be more easily infiltrated by a small, swift-moving force. With luck, they would all reunite at the base of Nightless City for the final assault. 

For the first three days, Wei Wuxian saw no one. The few villages that they passed had been reduced to barren husks, probably to prevent attacking armies from pillaging for supplies. They’d expected this, and brought along as much food and water as they could comfortably carry. Their golden cores would have to sustain them the rest of the way. 

Shijie had fretted over their meagre rations. “Are you sure you have enough?” she’d asked, cramming his and Jiang Cheng’s pockets with extra packets of salt and dried meat. “It’s so many days of travel; what if you get hurt?”

Wei Wuxian had thumped his chest proudly. “Don’t forget, Lan Zhan and I killed a Xuanwu even after four days without food or water. What are a few puppets compared to an immortal monster?”

That had made her laugh. Wei Wuxian smiled at the memory. He didn’t have enough, of course; he could hardly raise suspicion by bringing more food than expected for a cultivator of his level. But he trusted that Jiang Cheng would share if he whined enough. 

In any case, he was no stranger to hunger. 

On the evening of the fourth day, they were attacked. 

Wei Wuxian sensed it first when a strange energy shivered under his skin, like the pressure of an oncoming storm. The Yin Tiger Seal, tucked away in his qiankun pouch, began to pulse. He squinted at the gaps between the black spindly trees for movement, but found nothing. 

He stopped anyway, and grabbed Jiang Cheng’s arm to make him stop as well. “Something’s wrong.”

Jiang Cheng’s arm went iron-tight under Wei Wuxian’s grip. He followed the direction of Wei Wuxian’s gaze, sword-hand clenched on Sandu’s hilt. “What is it? I don’t see anything.”

Dusk stripped colour from the world, leaving only murky shades of blue and black. Wei Wuxian had fire talismans, but the smoke might give away their position. If only there was some kind of tool that could tell you where things were— 

Cool blue light caught his eye. Wei Wuxian turned and saw Lan Zhan, sword unsheathed. The bare blade glowed with his spiritual energy like a lamp in the darkness. The light painted deep, eerily shaped shadows in the forest around them.

They watched and waited, silent and still, holding their breaths. 

Nothing charged at them from the shadows, but the strange feeling didn’t fade.

And then someone screamed, a sudden burst of sound that cut off in a wet gurgle. Wei Wuxian spun around. A puppet crouched over the body of a Jiang sect disciple, lifting its bloody face from the gory ruin of the disciple’s throat. 

Jiang Cheng swung, and cut off its head. “Where the fuck did it come from?”

The hairs on the back of Wei Wuxian’s neck prickled. He looked up, just as Lan Zhan lifted Bichen high above his head. 

Wei Wuxian’s eyes widened. “They’re in the trees.”

The battle was bloody and brutal. 

Countless puppets threw themselves from the trees, slashing and tearing at any cultivator they could reach. No injury short of death stopped them; they attacked with blood gushing from gaping wounds or white spikes of bone poking out of mangled limbs. 

Wei Wuxian blew a shrill command on Chenqing, but that only froze them for a moment. Then they remembered that they were bound to an older, stronger power and tore off the cobwebs of his control. He switched to talismans instead, flinging spells for light, distraction, paralysis, binding — anything for even a moment of advantage. Chaos raged around him, swords clashing, flesh rending, people screaming as they bled, rose as infected puppets, and were cut down. 

By the time the last puppet fell to the ground, Wei Wuxian was exhausted. A pale orange moon hung high in the sky, casting sallow light upon the other, similarly exhausted cultivators. They leaned against their swords or tree trunks, many wounded, all panting harshly.

Nine of their own people lay dead among the puppets.

They didn’t have time to bury everyone. The best they could do now would be to cast a barrier seal around this place, to keep away scavenging animals until they returned from Nightless City. 

A flash of white snagged Wei Wuxian’s gaze. Lan Zhan, somehow still looking as pristine as fresh snow, sat down in the dust. He drew out his qin from his qiankun pouch, and began to play. 

The melody was unfamiliar, slower and simpler than the one he’d played for Wei Wuxian in the Unclean Realm. It soothed instead of cleansed, calming and quieting even the air around him. 

He tilted a questioning look at Jiang Cheng, who leaned in close and whispered, “It’s one of their Lan songs, used to put spirits to rest. I heard him play it when we were clearing out the Wen supervisory offices.”

Wei Wuxian frowned. Freed from Wen Ruohan’s control, the puppets’ spirits should have welcomed this musical escort into the afterlife. Instead, they resisted, twisting like caught fish in the net of Lan Zhan’s power. 

It would be futile, of course; Hanguang-jun’s will was unconquerable, and some of the weaker ones were already beginning to settle. But the freshly killed still snarled, voiceless and furious: revenge.

“Hey!” a voice called, interrupting the song. “This puppet is still alive!”

They all turned to see a Lan disciple point shakily at a body — no, not a body, a living puppet , half-disemboweled but still moving. It lifted its blood-splattered face and let out a howling wail, inhumanly loud and teeth-grindingly shrill. Wei Wuxian could hear the thing’s vocal cords strain and shred as the sound echoed through the forest, until a sword flew through its open mouth and impaled it to a tree. 

For a moment, there was only silence. 

Then Wei Wuxian felt the thunderstorm prickle again as low growls answered from the dark forest surrounding them. Like before, the Yin Tiger Seal pulsed to life. 

More puppets. The disciples staggered to their feet and lifted their swords with hands that trembled. Their faces were ghostly in the pale moonlight, grim and frightened. 

They were still three days from Nightless City, and every person they lost here was one person fewer to stand against Wen Ruohan. 

Wei Wuxian brought Chenqing to his lips. 

Do you want revenge?

He didn’t command, this time. He didn’t need to; the spirits cried out for the injustice of their deaths, their lost dreams and lost loves. 

Then stay with me, he offered. I will give you revenge. 

This was harder than when he was directing the slaughter in the Wen supervisory offices. There, he’d just needed to call out to the resentful spirits of Wen victims, gather them to him, and give them a target. But resentful energy alone wouldn’t be enough against Yin-manipulated puppet cultivators. Wei Wuxian needed flesh. He needed more. 

The Yin Tiger Seal’s power swelled like an overflowing river, flooding his hands, his lungs, his bones. Chenqing's song made the air shiver as one by one, the spirits returned to their former bodies.

I know who you need to kill, he promised, and ordered the attack.

The dead heaved themselves up from the ground and ambled towards the oncoming puppets. Jiang sect cultivators screamed and slashed at them with swords. Lan sect was still, wide-eyed but unmoving, held back by Lan Zhan’s outstretched arm. Wei Wuxian didn’t try to decipher the expression that was on Lan Zhan’s face. He turned to Jiang Cheng instead, and shot him a sharp, meaningful look. 

Jiang Cheng’s eyes flicked between Wei Wuxian and the newly revived corpses. He nodded once. “Stay calm!” he shouted at the disciples. “Wei Wuxian’s controlling them. They won’t hurt you.” 

Wei Wuxian dipped his head in gratitude, and continued to play. The corpses broke into an unsteady, lurching run, utterly uncaring of the condition of their bodies. Those without feet ran on bloody stumps. Unnaturally angled heads swayed above throats slit almost to the spine. The corpse of the puppet who’d summoned the reinforcements trailed a long rope of intestine behind him as he ran. 

The corpses slammed into the puppets and tore them apart. It didn’t matter that the puppets outnumbered them four to one; the Yin Tiger Seal gorged the corpses with resentful energy, giving them unnatural ferocity and strength. 

On Wei Wuxian’s next pause for breath, he said, “Go. I’ll catch up.”

Jiang Cheng glared fiercely at him for a moment, before his gaze slid to his disciples. “One hour. If you’re not back by then—”

Wei Wuxian rolled his eyes and jerked his head. Just go already.

“Fine,” Jiang Cheng said. He raised Sandu and began to run, yelling for the rest of the cultivators to follow. Jiang and Lan sect ran after him, and were engulfed by the deep shadows of night. 

Lan Zhan lingered, expression still unreadable. Wei Wuxian stuck out his chin confidently and raised an eyebrow, until Lan Zhan also turned and left. 

Alone, Wei Wuxian could focus on controlling the corpses. Not that much control was needed; the spirits wanted this, delighted in the destruction of their enemies. The resentful energy responded to even the smallest touch of his will, as eager as well-trained horses. 

As the last of the puppets collapsed, so did the corpses. Their resentment finally spent, most of the spirits dissipated of their own accord, content and satisfied. A few still wanted to stay, but he tightened his control and they obediently sulked off into the afterlife. When the forest was silent and empty once more, Wei Wuxian lowered his flute.

It was stunningly, exhilaratingly easy, in a way that nothing had been since the loss of his golden core. His mind was calm and clear. His fingers and lips felt numbed by the cold touch of resentful energy. 

He flexed his fingers, licked dry lips, and tasted blood. Wei Wuxian touched his upper lip; his hand came away wet. He stared silently at his red-stained fingers. 

It was suddenly very cold. Wei Wuxian tried to shiver, but found that he couldn’t. There was an icy numbness growing inside him, like the sprawling spread of frost, until the only warmth he could feel was the blood spilling from his nose. Chenqing tumbled from his grasp. He couldn’t stop it. He tried to walk, and stumbled.

White-clad arms caught him. He blinked blearily up at Lan Zhan’s face, so beautiful in the moonlight. Lan Zhan was saying something, but Wei Wuxian couldn’t hear. Why did Lan Zhan look so worried? Wei Wuxian had defeated the enemy. Maybe Lan Zhan was worried about him? But he was fine, just a little tired, Lan Zhan-ah, you wouldn’t mind just letting me lean on you for a moment, would you?

A hand touched his face, and heat was flowing into him, chasing away the cold like Shijie’s soup on a winter day. He pressed his face into Lan Zhan’s palm, wanting more.

Darkness welled up around him. Wei Wuxian closed his eyes, and sank down into the dark. 

Awareness seeped in slowly, an unwelcome intruder to the comfort of Wei Wuxian’s sleep. He kept his eyes stubbornly shut, but couldn’t stop the rest of his senses from awakening. Chenqing was quiet at his waist; that was good. There was movement, but he wasn’t moving. There were arms around him, tucking him securely against a warm chest that smelled somehow familiar— 

Wei Wuxian jerked awake, eyes flying open, and almost tumbled out of Lan Zhan’s arms before Lan Zhan tightened his grip. “What are you — why are you carrying me?”

Lan Zhan gazed impassively down at him. “You were unconscious,” he said, as though that was sufficient explanation for carrying Wei Wuxian like a maiden in a romance novel. 

“Well, I’m not unconscious anymore so put me down!” Wei Wuxian looked around frantically. Fortunately, they were alone in the forest. “Can you imagine if someone saw? I’d lose face forever!”

“You offered to carry me once,” Lan Zhan said.

“I have no memory of this,” Wei Wuxian declared. “Seriously, put me down.”

Lan Zhan looked like he wanted to say something in response, but sighed instead. He stopped walking, bent at the waist, and carefully lowered Wei Wuxian to his feet. 

“Thank you,” Wei Wuxian said primly, and almost immediately fell when his legs buckled beneath him. 

Lan Zhan caught him again, though this time he had mercy on Wei Wuxian’s bruised dignity and only braced his arm behind Wei Wuxian’s back. “You’re welcome,” he said coolly. 

It was slower going with Wei Wuxian walking on his own, but if Lan Zhan objected to the pace, he didn’t show it. A smear of red marred the immaculate white of Lan Zhan’s robes — probably from Wei Wuxian’s bloody nose, he realized guiltily. 

His nose wasn’t bleeding anymore though, and the icy numbness was gone. That inner frost had never happened before, though admittedly he’d had also never drawn so heavily from the Yin Tiger Seal. 

Wei Wuxian stopped. Yin metal — he’d always thought that the name was a coincidence, or some dusty, esoteric reference that he wasn’t learned enough to understand. But if it was actually yin energy… 

It would explain why he always felt cold now. And why Lan Zhan’s spiritual energy was so warm, because of course he’d be brimming with yang; that was probably why that bone-chilling Cold Spring hadn’t even fazed him. And if dual cultivation really did work, and required a yin and yang contributor, then technically— 

“Wei Ying.”

Wei Wuxian blinked, then realized that he’d just been standing there for — a while. “Oh, sorry, let’s keep going.” He took a step forward, but Lan Zhan’s arm tightened around his back, keeping him in place. 

“I… I have a question,” Lan Zhan said, sounding uncharacteristically hesitant. “Will you answer me truthfully?”

“Will you know if I don’t?” Wei Wuxian asked, and snickered when Lan Zhan glared at him. “I’m joking, I’m joking. Go ahead and ask.”

Lan Zhan took a deep breath, and met his gaze steadily. “What has happened to your golden core?”