“Kacchan! Look out!” Izuku’s voice pierced through the other sounds, green eyes honing in on something the blonde had missed. The alpha whirled around just in time, hands going out to steady the person shoved in his way. It had been a peaceful patrol, until five minutes from its end, when Izuku and Katsuki had stumbled upon some kind of brawl. Izuku was restraining the other person, a girl of about eighteen, and stopping her from trying to murder the boy Katsuki was now holding. Blue glowed at her fingertips, and neither hero noticed when her hand made contact with Izuku, light flaring before going out, as they were too occupied with trying to calm the teens down. A third stepped out from behind a tree, purple hair seeming to float behind her as she made her way over to Izuku.
“I’m terribly sorry sir, we were just trying to enjoy our drinks whe-”
“When this absolute fucking dickhead decided he can try and touch my alpha!” The other girl interrupted, teeth pulled back into a snarl and black hair coming undone as she thrashed.
“Oooh…” Izuku’s eyes lit up in understanding, it was common knowledge omega’s could be more aggressive if they felt threatened, Izuku just didn’t know people could be careless enough to push them that far.
“Yes, that.” The alpha flashed a sheepish smile at the heroes, light blush coating her cheeks. Katsuki reluctantly let the boy go, warning him it was ‘best to not fuck with anyone if they were mated’, and ‘no one woukd be there to save his useless ass next time’. It was actually quite tame for the hero. Izuku released the omega once the boy was out of sight, watching fondly as she started fussing over her alpha, who merely smiled, thanking the heroes before the pair walked back to the seat they’d been previously occupying.
“It’s been a while since we’ve had to break up this kinda fight.” Katsuki broke Izuku out of his thoughts, emerald eyes darting to red, flush spreading across freckled cheeks.
“Y-Yeah, you’d think people would know not to make omega’s feel threatened!” He laughed, voice higher than usual because when had Kacchan gotten that close? He hadn’t prepared himself for this, sure, the pair had gotten closer, almost back to where they’d been as children. Less friendly feelings had been plaguing Izuku for years, though, and when Kacchan was just… well, Kacchan, it made them all the more prominent, and Izuku just wanted to-
“C’mon nerd, we gotta get back to the office.”
“Of course Kacchan!” The omega scrambled after Katsuki, the itch to stay close to him even stronger than it usually was.
Izuku followed Katsuki through the agency doors, almost treading on the alpha’s heels, and getting yelled at for the trouble. The duo split at the door, Katsuki going to his office, and Izuku heading towards Ochaco’s. It was a ritual, after patrol he’d go to her office, and they’d relax and have cake. He didn’t know when it had started, but it was always a great opportunity to talk about… well… anything. Kacchan took up a fair amount, and Izuku hated to admit that, although his friend took any chance she got to bring it up.
“Oh, Deku! You’re back later than usual, I set everything up!” Ochaco greeted the omega as he sat down next to her on the office couch, sighing as he leant back and stretched.
“Kacchan and I got caught up last minute, just a minor brawl between two omegas.”
“Were there any quirks involved?” She asked, handing him a piece of strawberry cake.
“Not that I know of, they didn’t mention it or anything.” Izuku shrugged, using all the restraint he had to not shovel it into his mouth. He was ravenous, for some reason.
“Mmmm, anything new happen with Katsuki? You guys didn’t… have a quickie or anything on the way back?” There was a glint in Ochaco’s eye, the beta laughing when the omega began choking on his cake.
“How could you- Ochaco- I can’t even-” Green eyes watered as he spluttered, face flushing at the mere thought of doing anything with Kacchan.
“Uh huh, sure thing Deku.”
The omega left Ochaco’s office with the rest of the cake, and one of her sweaters shoved into his bag, he didn’t know why he’d needed it, but she’d laughed as she gave it to him, so it was okay. The lounge was quieter than usual, only Eijiro, Mina and Denki sitting there, babbling on about something that was lost as Izuku’s eyes zoned in on the snacks.
“D-Do you guys mind if I take some?” He inched closer, almost drooling at the food.
“Yeah of course man! Denki got way too much.” The redhead turned first, signature shark teeth flashing in the light. Izuku could only nod, happily taking the food and placing it with Ochaco’s sweater.
“Here, take these as well!” Mina appeared by his side, arms full of fabric. They were… sweaters? Hoodies? Of his friends at the agency, and Izuku was even more confused as to why he took them. Denki only snorted in response, impatiently tugging Mina back to the cuddle session he’d started with Eijiro.
“Hey, Kacchan… thought I’d give you some company!” Izuku chirped as he entered the blonde’s office, gym bag and paperwork in hand.
“I don’t fucking need any company, nerd.” Katsuki snarled, though really he was too busy shoving his alpha down, who was more than happy that Izuku wanted to be with him, to do anything to stop the omega. He grinned as he trotted in, snagging the spare clothes Katsuki had thrown over a chair. Izuku sat down right next to the blonde, opening his bag and this must be why he has the clothes! So he could get comfortable! With that confirmation he began arranging it all just right, Katsuki’s glare completely ignored.
The blonde, however, was freaking out. Because why was Deku here? With all these clothes? Like sure, he was… rather excited that the nerd actually wanted to spend time with him, bt he didn’t understand why. And what the fuck was with the clothes? And the food? Katsuki had no idea how the omega was scoffing it all down, he was actually impressed.
‘Okay, that’s just perfect!’ Izuku nodded to himself, sighing contentedly before he settled down in the middle, head pillowed on the biggest hoodie Kacchan had, which was drenched in his scent and absolutely divine. The whole room smelt like Kacchan, caramel and cinnamon and gunpowder, which somehow managed to not be off putting, to Izuku at least. He’d seen others wrinkle their nose at the smell, but a glare from the omega usually got them to stop. The blonde could barely focus on the paperwork he had, head swimming because Deku was there, and he was all apples and rain and freshly mowed grass and Katsuki couldn’t think around it, there was something different. His thoughts always went back to the omega, and how close he was, and how he’d chosen to come in here, he hadn’t been forced. Katsuki couldn’t understand why Izuku chose to come here, but he wasn’t going to push him away when he’d been hoping for something like this to happen for years now.
“Are y’all comin’? We’re leaving now!” Mina stuck her head through the door, not even blinking at the omega leaning against Katsuki.
“Fuck, is it five already?” The blonde stood up, startling a rather disgruntled omega, who made his… annoyance at being disturbed known with a growl.
“Shut the fuck up, Deku, it’s drinks night.”
“Oh? It’s that time already?” Izuku scrambled to his feet after Kacchan, stumbling and letting out a small ‘oh’ when Kacchan caught him, the blonde barely even complaining.
“You need to be more careful, I won’t always be there to catch you, Deku.” Katsuki shoved him away when he heard Mina giggle, his bared teeth making her shut up, but doing nothing to stop the smirk on her face as she walked back to the group with them.
Izuku followed Katsuki out, doing his best to keep a reasonable distance, but he just wanted to be close to Kacchan. The alpha in question, tired of his heels being stepped on, gave up and yanked the omega next to him.
“If you’re gonna stick to me, you may as well not be steppin’ on my heels as well.”
“Kacchan’s so nice!” Izuku chirped, too caught up in Katsuki to notice the looks the others were exchanging. Katsuki couldn’t deny it was nice to have Izuku clinging to him like this, warmth bloomed in his chest at how trusting he was. He’d always been too trusting, if you asked Katsuki.
The bar was dimly lit, and the group made their way to the usual booth at the back, the only one big enough to fit them all. Katsuki was the first to slide into the booth, closely followed by Izuku, and then Ochaco, who squashed the pair closer than they would have gone on their own. Mina came over with a rather impressive tray of drinks, placing it down before she sat next to Denki, the blonde shoving Eijiro to make some more room. Conversation started flowing with ease, they’d been friends for years, what else did you expect? Katsuki stayed quiet, too focused on Izuku, the way their thighs pressed together was making his brain short circuit. Izuku was just as worked up, stuck between doing everything he could to not touch Katsuki, and throwing himself over the blonde’s lap. They were both a mess, it wasn’t hard to see. The looks their friends were sharing certainly didn’t help, only serving to make the pair blush even more.
“So Katsuki, I heard you guys ran into some trouble on patrol?” Mina’s voice was teasing as she lured him into the conversation.
“Nothing much, just some omegas fighting.” The blonde shrugged, fingers tapping his glass.
“Kacchan was amazing! You should have seen the look on the omega’s face after Kacchan told him off!” Izuku piped up, grinning ear to ear and looking at Katsuki with nothing short of adoration.
“It was nothing, Deku. People should no better than to interfere with mated couples.” Katsuki shrugged the praise off, biting the inside of his cheek as Izuku moved closer, their arms brushing against each other.
“Talking of mating, have you guys found anyone yet?” Denki leant forward, eyebrows cocked.
Both of them flushed at this, Izuku frantically shaking his head and Katsuki merely muttering a ‘don’t have the time.’
“So Katsuki, you and Izuku seem to be gettin’ close, huh?” Mina sidled up to her friend, Denki and Eijiro following her actions. Izuku and Ochaco had gone to the bathroom, and they were taking the chance to interrogate him about the omega.
“I don’t know what you’re talking about.”
“C’mon man, we’ve been friends since highschool, we know you’ve liked him since then.” Eijiro slung an arm over Katsuki’s shoulders.
“Awww, do you love him?” Denki mocked, he was asking to get his face blasted, in Katsuki’s opinion.
“You must, to have been pining all these years. It’s obvious he likes you too!” Mina couldn’t help but add.
“Shut the fuck up or I’ll kill all of you.” He hissed, eyes honing in on Izuku as soon as he was back in the room. The omega in question was drunk, stumbling and giggling while he leant on Ochaco. Katsuki had to push his jealousy down, because Izuku should be leaning on him. The blonde wasn’t much better, it was taking everything he had to not stumble when he walked.
“Oh Ochaco look! It’s Kacchan!” Izuku all but screamed, running full pelt to wards the alpha, who was too shocked to do anything other than brace himself for the impact. They didn’t fall, but Katsuki did have to stumble back a few paces to keep them upright, trying to ignore the snickers from their friends.
“Y-Yeah, we have got to get you home.” The blonde shook his head, thankful they lived in the same building.
The group had split, goodbyes and small talk exchanged before they headed their separate ways. It was only a five minute walk, but Izuku was making it his mission to stick to Katsuki like glue.
“I wanna stay with you tonight Kacchan, Can I? Please?” There were the puppy dog eyes, and who could resist them? Katsuki certainly couldn’t, letting out a sigh as he dug around for his keys.
“Yeah, of course you can Deku. You have a key to my apartment for fucks sake.”
“Thank you Kacchan! You’re so nice!” The omega snuggled closer, if that was possible, and this was going to be the end of Katsuki. They finally, finally got to Katsuki’s apartment, the alpha’s face on fire as he deposited the omega on his bed.
“Stay here, I’ll get ready for bed and get you something to sleep in. You got that Deku?”
“Yes Kacchan!” Izuku nodded, grinning as he watched Katsuki enter the bathroom, door shut behind him. The blonde collapsed against the door, what the fuck was up with Deku? He never acted this… clingy? He didn’t mind it, far from that actually, but it was so, so confusing. Katsuki felt like he could explode from how flustered he was.
Izuku was bored, he’d tried waiting, like Kacchan told him to, but he was restless. Tiptoeing as to not alert the other, Izuku went over to the cupboard, stripping his shirt and pants and leaving them in a heap. He quickly found a big shirt of Kacchan’s, deeply inhaling before he slipped it over his head. He wanted more of that smell, wanted to cocoon himself in it until there was nothing left. With that in mind, the omega started grabbing anything he could, while still sticking to the softer materials. He deposited them on the bed, going back and forth until he was satisfied. Then he began arranging them, getting them just right and fluffing the pillows until they were perfect. Izuku was so caught up in what he was doing he didn’t notice the red eye that peeked out from the bathroom.
“What the fuck. What the- what the fuck.” Katsuki choked, locked back in the bathroom with his face so red he felt like he was burning up. What was Deku doing?
“Hello? This better be good Katsuki.” Mina answered on the first ring, and the blond let out a sigh of relief. She was an omega, she’d know what was happening.
“Something’s wrong with Deku, he’s acting weird.” Katsuki spoke in a hushed whisper, glancing back at the door.
“He’s in pre-heat Katsuki, which is weird because we’re on the same cycle, but sometimes things can trigger-”
And then he remembered, the girl, the blue light.
“Can quirks trigger it?”
“Yeah, it’s actually pretty- Denki if you set anything on fire I swear to god- sorry Katsuki, it’s actually pretty common.”
“What the fuck do I do?”
“I thought it was obvious, you two are crazy about each other. Pre-heat can kind of… take away your impulse control? Izuku’s actions are all him, he’s just been pushing them down. I gotta go now before Denki and Eijiro do something stupid, good luck!”
And with that she hung up, leaving Katsuki an absolute mess.
“Uh, Deku… are-are you nesting?” Katsuki finally had enough control to go back to his room, although the sight of Izuku only in his shirt and boxers almost sent him back to the bathroom. Izuku seemed to war with himself, eyes widening before narrowing again.
“I-I’m sorry Kacchan! I don’t kno-”
“It’s okay, shithead.” Katsuki walked over to the bed, sitting down and tugging Izuku into his lap. “I’m… glad… that it’s me, and not some stupid fucking extra.”
“It’s always been Kacchan.” Izuku peered up through lidded eyes, blush coating his cheeks. “Does this mean that-?”
“Yes, Deku. I love you, and I’d be honoured to be your mate.”
“Oh Kacchan! I love you too!”