Chapter Text
The doctors had warned Mitsuki, Masaru, and Inko.
If they let little Katsuki and Izuku spend too much time together, the risk of them imprinting on each other raised exponentially with every week.
But how could they possibly expect Inko and the Bakugou’s to separate the tiny babies, who looked so angelic cuddled up next to eachother in one of their cribs, only ever so at peace when the other was near? How could they keep them apart when they were fussier without the other, practically sparkled when the other was in sight, babbled happily when they were touching? The parents weren’t cruel. They couldn’t do that to their boys, who had made their point clear from the very moment they met.
Katsuki had been extra fussy that day, three months old and not a quiet baby by any means, and the Bakugou’s had finally been cleared to take him with them to visit Inko and her newborn in their apartment. They had been present for the birth, of course, but tiny Izuku had been busy processing the trauma of being born that day, and hadn’t properly met them yet.
Katsuki cried and wailed and twisted his pudgy body, and Mitsuki loved him more than anything in the world, but she was exhausted, and she dearly hoped Izuku wasn’t in the middle of a nap Katsuki could wake him up from. Maseru dug out their key at Inko’s door — they were practically living together at this point, since they obviously were not about to let their favourite friend raise a newborn by herself — and stepped in, toeing their shoes off and announcing their presence.
Inko popped her head out from the kitchen with bags under her eyes but clearly happy to see them again, bouncing a dozing Izuku in her arms. Shoot. Mitsuki wished Katsuki would quiet down a little. He was still fussing, whining, and Mitsuki adored every noise he made, but Inko looked so tired.
Baby Izuku sleepily turned his chubby, wispy head at the noise, his whole weight on his mom. Mitsuki stepped forward to greet Inko properly and say hello to Izuku again.
Suddenly — silence.
Mitsuki blinked in confusion. She turned her head to find Katsuki staring at Izuku with the same level of focused attention that he gave the bright lights on the TV, sometimes, or the noise-making toys he loved the most. Mitsuki was a bit taken aback at the single-minded focus he was exhibiting, but the three adults watched quietly as Katsuki stayed perfectly, blessedly calmed, apparently enraptured by the tiny boy in front of him.
His tiny hands gripped tightly onto Mitsuki’s shirt, twisting the fabric, as he stared as if caught, every trace of frustration erased from his being. Izuku stared back sleepily, entirely content. Katsuki turned his head to his mom and babbled happily, finally at peace. Mitsuki looked at Masaru, then at Inko, laughing a little at their twin surprised expressions, and at her own relief. Katsuki was an infamously fussy baby. He had never quieted so quickly like this before, even when Mitsuki and Masaru tried filling every need of his they could think of.
A faint, foreign scent was wafting from close-by. Mitsuki gasped in surprise. What—
Inko and Masaru were both betas, so they couldn’t tell, but Mitsuki was picking up something— she stared at Izuku, then at Katsuki. Twin pleased scents, ever so light and tinged with something milky, were coming from their sons, one hickory-sweet and one a warm spice. Almost unheard of; children didn’t start releasing scents until their first strong mature emotion, sometimes joy, anger, even jealousy. To think that their boys would react like this just to their meeting—
It was almost like they recognized each other.
And so the Bakugou’s and Inko did nothing to hold the boys back from how much they seemed to want to be near each other; it brought them that specific joy only a parent can feel, to see their tiny boys so happy, so at peace with their friend.
So the incident had, in a way, been preventable. Had they listened to the doctors.
Izuku and Katsuki grew up thinking their bond was perfectly normal. They just did what felt right, and that often meant holding hands and rubbing wrists and ducking into each other’s necks. It was all innocent, sweet even, their little bodies pressed into each other’s sides with the lack of care for personal space most small children have, except their behaviour was as purposeful as it was unconscious, as they let themselves do as their instincts said would feel best.
Just as they had cuddled in the same crib as babies, they cuddled in blanket forts their parents made as toddlers, splayed out like starfish with an arm over the other’s chest, or one spread out and the other curled half on top of them. They held hands walking to recess in kindergarten, and their teachers knew better than to separate them.
Onlookers cooed at the sight of Katsuki’s face shoved in Izuku’s neck, assuming they were mimicking the behaviour of their parents or lovers in films. They didn’t realize Katsuki had always been able to pick up Izuku’s scent, and vice versa, even if others couldn’t. They’d mentioned it on the playground once, when they were four, and the others had been so confused that they decided not to bring it up again, and promptly forgotten about it, because they were four.
So as they grew, got older, taller, more knowledgeable, they didn’t think much of sharing clothes because they liked the way they smelled, sharing space more often than not, practically smelling like each other. They didn’t think anything of it, that is, until they were 14.
And they both presented, officially.
“Whoa, Midoriya!” Ryuu, one of their classmates, said one morning when Izuku came back from the restroom. Izuku froze in wiping his hands on his garukan — he winced at being caught, but they’d been out of paper towels in the boys’ room. Katsuki shook his head at him from his desk, and Izuku stuck his tongue out childishly in response. He looked back at Ryuu, who was gaping.
He didn’t think it was that big of a deal. “What?”
Ryuu was breathing in deep, for some reason, chin angled towards him like a hound’s snout. “You smell… like, really good!”
Izuku and Katsuki stiffened at the same time, gazes whipping to each other then to Ryuu.
“Wh.. what?” Izuku croaked. No one had been able to smell him other than Kacchan, and Auntie Mitsuki a couple times when they were younger.
Kacchan’s face was stony, barely blinking as he practically glared at Ryuu, who didn’t notice as he gushed at Izuku.
“Yeah, it’s like… kind of earthy and sweet! Did you present recently?”
Oh. Oh, no.
Kacchan shot up out of his chair, the metal scraping and startling their classmates, especially Ryuu, who hadn’t noticed him paying attention. Noses crinkled across the classroom at the same time as Izuku’s did, for the first time in their lives, as Kacchan’s smoky spice-tinged took a sharp edge. Izuku had smelled this before — when someone tripped him on the playground, when another boy tried to hold his hand. But he’d never in his life seen other people react to it too. It was a bit unnerving.
Only presented individuals could pick up on scents, typically, just like how only presented individuals typically gave them off. Katsuki and Izuku had always been a strange exception, and only with each other — until now. Katsuki grabbed Izuku’s garukan and yanked him out of the classroom, out of the prying noses of their presented classmates and their curious eyes.
Katsuki pulled Izuku to the stairwell, the both of them slipping inside quietly, and pushed him gently into the wall. Izuku leaned on it gratefully, staring up at Katsuki with wide eyes, who looked back with an identical expression.
So. That explained yesterday.
The evening before, Katsuki had presented. None of them had known when it would hit for either of the pair, middle school being the typical age for presentation, but their parents knew they were special, after Mitsuki had shared how she had picked up on scents from them at an incredibly early age. It would be random, a secondary-gender specialist had guessed, when their parents took them in one day in kindergarten. Katsuki and Izuku had finally asked why the other kids couldn’t smell them the way they could smell each other (they hadn’t even considered asking why no one else had smells), so their parents had decided it a good time to get some questions answered for them all.
So they knew it was coming, that one of them would eventually present first, randomly.
But what no one had told either of them exactly what presenting would mean. That Katsuki would suddenly be filled with heat, and raw emotion, skin itching for a horrible flash before everything settled, colours weirdly brighter, and everything smelled. Katsuki had shaken himself off, a bit rattled but somehow more… himself, all of a sudden, like the jigsaw pieces making him up had all shifted a little closer, were just that much more coherently him inside.
Also, he felt fucking invincible. Ferocious. So he was probably an alpha like his mom.
Katsuki looked up from where he’d been rubbing his suddenly sweaty palms on his pants, pleased. He wondered what Izuku would—
He blinked, freezing. Izuku was staring at him with even larger eyes than normal, glazed-over and almost dazed, pink rising in his cheeks.
“‘Zuku?” Katsuki asked, a bit concerned. “The fuck is up with you.” He reached out out of habit, brushing fingers over Izuku’s wrist instinctively, and Izuku shuddered. Katsuki stilled.
He’d never reacted like that before, so accustomed to their physical intimacy, the closeness that they’d always known. What was happening?
Katsuki shifted closer, more firmly encircling Izuku’s delicate wrist in his hand, noting how pretty Izuku looked with a blush sitting on his cheeks. He frowned, no doubt letting out a complicated mix of pheromones, although he couldn’t really smell them himself.
And Izuku—
Izuku whimpered.
A flash of heat shot through Katsuki instantly at the sound, his brain short-circuiting. He had never heard anything like that from Izuku in their lives, and now something deep within him he’d never interacted with before was whining and howling at it, scratching against its walls, wanting to hear it again. Something primal, insisting to make Izuku sound like that again. And this was all before Izuku’s scent, which had always been lovely but faint, since they hadn’t presented yet — Izuku’s scent suddenly exploded, flooding the air and wafting into Katsuki’s very brain, it felt like, saturating him in something earthy and sweet.
“Kacchan,” Izuku breathed, whined, body leaning forward helplessly, like every atom was reaching for him. They stayed separate, both unsure what would happen.
Was this what Izuku had experienced, when Katsuki had presented just now? Katsuki swayed in his spot on the bed, closing his eyes and breathing deeply, leaning forward unconsciously to get more, more, more. The scent was delicious, calmed something down right to Katsuki’s bones, filled him with warmth and joy and affection and—
Katsuki paused, straightening up suddenly at the implication. Wait. Izuku was presenting?
Which meant Izuku — Izuku had bloomed for him.
“Fuck,” Katsuki groaned, eyes nearly rolling back in his head at what just the thought of that did to him. His Izuku, blooming for him, for Katsuki and Katsuki alone. He reached out for the now heavily blushing Izuku, who was whining slightly, and pulled him into his lap. Izuku went readily, sighing as they pressed against each other, something somewhere deep clicking in place for both of them.
Katsuki groaned again as he shoved his face in Izuku’s neck, drinking in his newly-presented scent, the one no one else had ever experienced, his own body burning at the thought. Actually, every place they touched felt like it was on fire, heat seeping through their clothes, liquid flame dripping into his skin where their bare skin touched, especially where Izuku’s face was similarly shoved into Katsuki’s neck. Katsuki huffed and grunted, nuzzling in deeper, deeper, holding Izuku impossibly closer while Izuku whimpered and did the same.
So. Yeah. Yesterday had been an experience, to say the least. When they had finally peeled themselves off each other, they had just repositioned to cuddle instead, enjoying their new noses and each other’s newly vibrant scent. Apparently, according to Izuku, Katsuki’s had always been impossibly warm in an almost spicy, musky way, like saffron or sandalwood, and it was now rich and strong like an alpha’s. And Katsuki had explained to Izuku how his was like jasmine, and the smell of earth during a thunderstorm, like gentle surety and ozone, now more potent and alluring like an omega’s.
What they had failed to consider, so wrapped up in themselves, was that for the first time in their lives, other people would be able to smell them too.
Katsuki was clearly not very happy about that, if the dark scowl and glances at the door were indicative of anything. And Izuku wasn’t sure he loved it either. They had always been — just each other’s.
“We can wear scent patches in public, Kacchan,” Izuku said gamely, deciding to be reasonable. “We have to wear them in school anyway.”
Katsuki twisted his face up. His mom always whacked him and said he’d get wrinkles if he kept that up, but it was such a Kacchan way of expressing himself. “Then I won’t be able to fuckin’ smell you in public, moron. That’s.” His mouth pulled to the side unhappily. “We’ve never — before.”
Izuku wrapped his arms around Katsuki’s middle and tucked his head under his chin the way they both liked. Katsuki instinctually nuzzled into his curls, his wrist coming up to scent Izuku’s neck while the other settled on his waist. Izuku preened at the action, then replied, “I know, Kacchan, but we don’t have a choice anyway. And…” He poked his head up, chin on Katsuki’s chest, pouting slightly while Katsuki looked down at him with an begrudgingly endlessly warm gaze. “I don’t want everyone smelling you anyway.” He finished quickly, the last half muffled as he ducked his head back down to press his face into Katsuki’s uniform.
Katsuki chuckled and Izuku peeked back up, automatically smiling. “Possessive little shit,” Katsuki said amiably, the hands on his waist moving so his arms were comfortably looped around Izuku. Even as he said it, he pulled Izuku closer, large palms moving up and down his back greedily.
“Sure, Kacchan. I’m the possessive one,” Izuku said, rolling his eyes. Katsuki’s eyes darkened, frown lines reforming as he growled.
“Those bastards better stay the fuck away,” from you, he didn’t say, but that much was obvious. “Ryuu’s been eyeing your goofy ass for years. And that Hiroko dick.”
“Kacchan,” Izuku reprimanded exasperatedly. Ryuu was the same boy who had innocently tried to hold Izuku’s hand that one time when they were in kindergarten, and Katsuki had never quite let that go. Izuku was certain it was purely friendly interest, and had even said so early last year, but Katsuki had huffed and pouted and fussed until Izuku had dropped the subject. Something about alpha intuition, even if Izuku teased that they didn’t know whether he was an alpha yet. Ryuu was, incidentally. Which in hindsight may have been why Katsuki had always puffed up his feathers in warning subconsciously around him.
Despite their pouting, all of this was well and good. Katsuki and Izuku grew accustomed to their stronger scents and noses and controlling them, Katsuki physically fighting off their parents from cooing over his budding alphan traits. But then, later that year, Izuku was approached by another student, a boy just a bit taller than Katsuki, broad-shouldered and definitively alpha.
He asked Izuku to try out a new ice cream shop with him, and Izuku, stupidly, said yes.
“You what.” Katsuki snarled when Izuku mentioned it later, the two of them hanging out in Izuku’s room. Izuku stopped for the first time to consider the implications, then immediately flustered.
“It’s not like that!” He cried, waving his arms. “Or… maybe it is? I’m not sure… wouldn’t he say? No, maybe not. But it doesn’t matter,” Izuku looked up, boldly meeting Katsuki’s glare head-on, “It’s not like you and I are dating, Kacchan!”
Ah, shit. Rest in peace Midoriya Izuku.
For a moment, silence. Izuku watched Katsuki grow slowly redder with pure rage in real-time, distantly. He’s accepted his imminent death.
Then:
“FUCKING WHAT.” Katsuki exploded, literally and figuratively, little bursts popping in his hands. “DO YOU THINK YOU DON’T BELONG TO ME, YOU DIMWIT.”
“Kaccha—”
“DON’T YOU KNOW YOU’RE MINE.” Katsuki was catatonic, stomping towards him. “DO YOU NEED MY FUCKING BITE TO UNDERSTAND THAT? IS THAT IT? I’LL DO IT RI—”
“Kacchan!” Izuku finally got in, glowing red and flustered beyond belief at the talk of mating bites, of all things. Katsuki could be so dramatic. “I just meant we’re not officially dating, so he didn’t do anything wrong!”
“I’ll show you wrong,” Katsuki growled, looking murderous, eyes unfocused as he sneered at something Izuku couldn’t see. “I’ll kill him.”
“Jesus, Kacchan.”
“He had no fucking right—”
“Kacchan, we’re both unmated—”
“You smell like me.” Kacchan interjected ferociously. “I’ve made sure of it.”
Izuku paused, and Katsuki blinked rapidly, like he hadn’t meant to say that. Sure, they scented each other often, but Izuku had assumed it was a comforting thing out of instinct, the way it had been when they were little kids. Even if it felt different, better, now, Izuku didn’t think—
“You’ve been scent-marking me?” Izuku asked carefully, searching Katsuki’s face. Katsuki paled.
“I— it’s just—”
“It’s just what?”
“Goddammit, Izuku,” Katsuki muttered, rubbing a hand across his face and scrubbing at his hair.
“You don’t know— what you do. To me.” He hesitated, finding the words. “Ever since we presented it’s like— it’s not enough. To have you in private. I want you — all the time.”
Izuku swallowed. “You do have me all the time, Kacchan.” They were more than best friends, they were — whatever they were, but it meant everything, to Izuku. He thought Katsuki knew that.
“No, I—” Katsuki groaned in frustration. “I know we’re not. Together like that. But I don’t want— I want you to be mine and no one else’s, sometimes. All the time, actually. It’s — overwhelming, how much I want— need that.”
Oh. Izuku breathed in shakily. “That’s not fair, Kacchan.” Not when Katsuki would never want him the way Izuku secretly did, when he laid in bed at night, surrounded by Katsuki’s scent from the day together and from the shirt of his he was probably wearing. Not when he meant in an instinctual, alphan way, and not the painful way Izuku experienced the same sentiment.
Katsuki closed his eyes as if in pain. “I know.”
A beat. Katsuki opened them again suddenly, jaw tightening. “Go on your stupid fucking date with that extra. See if I care.”
“Kacchan—”
“I’ll prove it. Prove I don’t — care. You’re right, it’s not fair of me to ask… that. Of you.”
Izuku’s heart hurt so badly, and he didn’t really know why. But something inside of him was clawing at him, whining and wailing pitifully, begging him to go to his— but Kacchan wasn’t his like that, even if they were incredibly close. Codependency, Auntie Mitsuki had said once, shaking her head. That’s all it probably was, Izuku had thought, and neither of them had done anything to ever suggest otherwise.
Even now, Katsuki was backing away, probably only reluctant out of misplaced pride.
The date, which Izuku realized five minutes in really was A Date, went okay at first. It was nothing special, which Izuku suspected was because he kept turning to Katsuki to mention something, only to find either an empty space, or his date, Fuminori.
The ice cream was nice, at least, the sky clear, everything perfectly fine. Even if Izuku missed Katsuki terribly, wondered what he was doing, who he was with, if he missed Izuku, maybe, the way Izuku missed him. Which was silly, Izuku scolded himself, they’d just seen each other a few hours ago, walking home from school. They usually both went to one of their houses, but today they had split up, Katsuki mumbling something about chores after Izuku mentioned needing to get dressed to go out.
They usually did their chores together, but whatever.
“Midoriya?” Fuminori prompted, and this was wrong, all wrong, he should be here with Kacchan, Kacchan liked this flavour of ice cream and Izuku didn’t, he hadn’t even wanted it, he’d just been thinking about him, daydreaming like he always did when they were apart. He missed him, he wished he were here, if only, if only, if only—
“Whoa, Midoriya. You okay?” Fuminori was waving a hand in front of Izuku’s eyes with a scrunched-up nose, brown eyes concerned.
They were the wrong colour. Izuku wanted to throw up.
“I’m fine,” Izuku said, straightening. Stop ruining the date! Izuku scolded himself. Just enjoy it! Kacchan will never want you like that, so let him go!
Ha. If only it were that easy.
“Maybe we should go,” Fuminori said with scrunched-up eyebrows. “You’re almost done anyway.”
So he was. Izuku stared down at his ice cream cup. When had he done that?
They cleared their table and left, Izuku relaxing when the cool outside air hit his face. It really was a beautiful day. Maybe he could enjoy this, meaningless as it was.
They made their way to a nearby park, Fuminori leading them, Izuku basking in the sunshine like a lazy cat. Fuminori kept glancing at him with furrowed brows, hunched a little the way people who weren’t quite comfortable with their height yet did. He finally pulled up to a stop under a gazebo, the area surrounded by trees to give the illusion of seclusion.
“Can you even smell me?” Fuminori snapped.
Izuku tensed at his tone. “Huh?”
“I’ve been pumping out pheromones for, like, twenty minutes. You didn’t react at all.”
Izuku didn’t like his attitude. “Uh…. sorry?” In truth, he hasn’t picked up anything. Honestly, he barely smelled anyone who wasn’t Kacchan unless he focused hard on their scent.
“No, you— that’s impossible. You should be affected.” Fuminori sounded a little crazed.
Izuku was getting a very bad feeling about this. “What are you talking about?”
The taller boy made a frustrated noise. “You’re an omega. That’s how it works.”
What the— Izuku took a cautionary step back, creeped out. “I don’t think— what are you even trying to do?”
Fuminori wasn’t listening. “Like— watch this.”
That little voice inside of Izuku was telling him to RUN. Izuku, stubborn, held his ground. He was training to accept One For All. He could probably end up ensuring this guy would never have kids if it came to it.
Fuminori leaned down a little, right on the edge of Izuku’s personal space, that line that didn’t exist to Katsuki and their families but was solidly in place for everyone else.
Fuminori opened his mouth, and when he spoke, his voice had an odd tone to it, rumbly and intentional, reverberating in Izuku’s ears:
“Kneel.”
The simple word carried a weight Izuku couldn’t decipher, like there should have been more he picked up, but any underlying characteristic lay just beyond his reach. Izuku blinked at the other boy, confused, then even more confused, but this time mixed with disgust.
“Excuse me?” Izuku spat. “What the hell?”
Fuminori looked lost, and uncomfortable. Frustration was brewing behind his eyes. “What’s wrong with you? Are you broken?” He demanded.
Izuku had never been so unsure-footed in his life. The ice cream turned acrid in his stomach. “Did you expect that to work?”
“It was a Command, Midoriya. It’s not supposed to not work.”
Oh. Izuku has heard of Alpha Commands. They weren’t very ethical, pretty frowned upon, actually.
They also always, always worked on an unbonded Omega.
For a moment, Izuku was so preoccupied dealing with his mind whirring over that crisis, that he didn’t notice Fuminori coming closer until he was right up in his space, way too close.
“Whoa—” Izuku tried leaning back, but his back was to the railing of the gazebo. He raised his arms to pushed Fuminori back by the shoulders, but the other boy caught his wrists, ducking his head down to his neck to—
scent him?!
Izuku kneed him in the balls, kicked him in the stomach for good measure, and ran off.
Jesus Christ. People sucked sometimes. Izuku rubbed at his neck, unnerved by the slight scent of foreign alpha that Fuminori had left behind. It was on his wrists, too, meaning three whole scent glands were affected. Izuku had wipes at home, at least. Kacchan hated them, because they “muffle your fucking flowery shit,” whatever that meant, but Izuku and his mom still kept some for emergencies.
Izuku walked home, enjoying the fresh air again. He dug through his backpack for his keys and unlocked his front door, noting one of their plants needed pruning. Once inside, he checked the medicine cabinet — damn. No scent-nullifying wipes. His mom was at work; he’d have to ask her to buy more. Oh, maybe he had some in his room.
To Izuku’s surprise, Katsuki was hanging out at his desk when he stepped inside, twirling in his roller chair with his long legs stretch out in front of him, tapping at his phone. Katsuki looked up as Izuku walked in, pupils dilating, then shrinking. He seemed to be restraining himself, stiff as he held his breath and held himself back, looking Izuku over from head to toe. He was almost trembling with the effort, Izuku noticed, endeared. Then Katsuki’s nose twitched.
Katsuki took one whiff of Izuku and immediately pounced, snarling.
Izuku eeped as he was shoved into the wall, head bouncing in something soft. 170 pounds of alpha launched at him, enveloped his senses completely. Katsuki’s scent was furious, reaching, sharp and potent and overwhelming, darkened at the edges with something Izuku couldn’t quite place.
(But his hand had come up around the back of Izuku’s head, so he wouldn’t bump it on the hard wall. Kacchan never let him catch a break, honestly, in Izuku’s quest to smother his feelings.)
Katsuki crowded him into the wall, their bodies lined up, Katsuki’s larger frame shadowing his. “What the fuck— why— he— you let— hrrgh,” Katsuki was incoherent with rage, eyes almost completely black. Katsuki’s face shoved into Izuku’s neck, nuzzling roughly, the bigger boy sniffing and grunting angrily.
Katsuki was beside himself. The moment Izuku has walked in, something in him had calmed, happy to see the omega again, but still pacing in worry over what he would find. He told himself not to react if Izuku had signs of — embracing another alpha. But he could only prepare himself for so long and finally had to breathe in, and when he did, his stomach had dropped, something hot and acidic filling the pit of his abdomen. He could smell that bastard on him, traces of his slimy scent on Izuku’s. Not enough to be a claim, or even count as scent marking — just enough to be evidence the asshole was there. There, on Izuku, which he had no fucking right to be. Katsuki saw red.
He launched himself out of the chair to smother Izuku in the scent he was supposed to be covered in, the one he could still smell on him, but not enough, not enough to overwhelm that other fucker’s. Izuku squeaked but Katsuki barely heard him, was barely aware of what he was doing, instincts overwhelming him with a need to remark his claim, claim, claim.
“Shit, fuck — goddammit, ‘Zuku,” Katsuki growled. It wasn’t enough. He opened his mouth, lips hovering over Izuku’s neck, then closed it again.
What was Izuku doing to him? It was like all the urges he’d been barely repressed had rushed to the surface in full force, something in him howling, furious at the traces of another alpha on his, his—
Katsuki froze. Oh. He took a deep breath, forcefully relaxing his tensed muscles, shifting to lay his forehead heavily on Izuku’s chest. Shit.
So that was why. Katsuki’s stupid fucking alpha hadn’t gotten the memo that Izuku wasn’t his. Not his alone, the way he wanted, like he had embarrassingly revealed to Izuku in an outburst the day before.
Izuku’s hands had come up automatically around him as Katsuki let out a heavy, resigned sigh into his shirt, one hand carding into his hair and the other on his back.
“Sorry,” Katsuki muttered, drawing back. Izuku let out a breath.
“It’s okay, Kacchan,” he said, a bit shakily. “That was a lot more welcome than when Fuminori tried it.”
Something hot flashed through Katsuki’s core, his blood turning to ice. He almost didn’t want to know what Izuku was implying.
“What do you mean?” Katsuki growled slowly, warningly, the back of his mind surprised at how much deeper his voice had pitched unintentionally.
Izuku scratched the back of his head. “Ah, he kind of… came onto me without me wanting him to. He tried to use a Command? To get me to kneel.” Katsuki froze. Izuku continued, “I kneed him in the balls but he kind of scented me before I could get away.”
Katsuki stared, uncomprehending. Mind blank, a last futile attempt by his subconscious to stop him from doing something unforgivable. Then the audacity of the other alpha suddenly hit him like a mallet to the skull. He could feel something creeping up his veins, something ferocious that laced his tongue. He looked at Izuku, who stood fidgeting, and a draft from the overhead fan momentarily wafted that foreign alpha stink into Katsuki’s nose again.
All coherent thought flew out his head.
Izuku watched as the other stilled. Then Katsuki’s eyes went black.
“Kacchan…?” Izuku asked, hesitantly, but Katsuki didn’t answer, just stepped into him and leaned forward slowly, so Izuku heated up one desperate degree of Katsuki’s body warmth at a time. Katsuki’s mind was clearly somewhere else, or gone, like he was listening to something inside, his eyes unfocused but expression sharp. Big hands pressed Izuku back into the wall by his shoulders, then slid down, wrists purposefully dragging across his clothes, palms cupping his waist, then back up, coming up to his neck and into his hair. Katsuki made direct eye contact with Izuku as he rubbed his wrist on Izuku’s neck scent gland boldly, the other hand gripping his hair to tilt his head to the side. Izuku shivered. Something about the look in Kacchan’s eyes, the purposeful movement, made the silence feel charged.
“Izuku,” Kacchan growled, and Izuku’s stomach erupted in butterflies at the impossibly deepened, gravelly pitch.
“Kacchan, are you — oh—” Izuku gasped as Katsuki ducked his head to drag his nose up the side of Izuku’s neck, still holding his head to the side with a gentle but firm grip on his curls, the other hand back to sliding boldly up and down his waist. The touch left a trail of magma in its wake, and Izuku was so busy shaking at the possessive scent flooding his senses that he didn’t notice how Katsuki’s eyes narrowed, mouth opening—
until something hot and wet dragged a wide path up his neck, right over his scent gland up to his jaw.
Heat shot through Izuku so fast it made him dizzy. Katsuki dragged his tongue over his scent gland again, groaning and panting, and if he kept this up, Izuku would have to change into new pants.
“Kacchan, please,” Izuku whined, but it sounded more like a moan, and Katsuki responded with a groan of his own, muffled into Izuku’s neck as he pressed his large body even closer. Until all Izuku could see, smell, feel, was Kacchan.
Kacchan, Kacchan, Kacchan, just like it had always been.
“Did you do it?” Katsuki breathed into his ear, Izuku tipping his head back on instinct at the deep rumble and the hot breath on his ear. The motion incidentally exposed more of his neck, as if in offering, one Katsuki took gladly, shoving his nose in again and bringing the hand in Izuku’s hair down to cup his neck, a thumb pushing at the underside of his jaw to hold his head back and throat bared.
“Did you?” Katsuki demanded insistently, forcefully restrained, and Izuku’s head was full of cotton and the scent of Kacchan’s protective anger, dizzy from all the blood rushing to it. He blinked slowly, feebly trying to regain some coherency.
“Did I… what… Kacchan,” Izuku all but moaned, Katsuki not letting up from his scavenge across his sensitive scent glands and surrounding skin.
Katsuki let out a low noise from the back of his throat, angrily. “Kneel,” he said, and belatedly Izuku realized he had just been answering his question, but it was too late, Izuku had already slipped down onto his knees automatically, looking up at his— at the alpha above him, eyes probably swirling with the effect of the pheromones in the air mixing with his own secret desires.
Katsuki’s eyes were wide, pupils impossibly dilated, pumping out a scent so strong and rich and pleased that Izuku actually swooned, something in him practically purring at provoking the reaction.
The light was weird in here — no, Izuku’s pupils must be dilated beyond belief, he realized, but it didn’t matter, as long as he could see Kacchan, feel Kacchan. Katsuki’s hand had slid back up on Izuku’s movement down, fingers tangled in his hair and palm cradling his jaw, thumb resting on his cheek.
Katsuki squinted, blinked— he looked a bit confused. Izuku wanted to help, so he pressed his face into his pants leg in consolation, nuzzling the fabric, appreciating the hard muscle underneath. He wasn’t sure what to do with his hands— he raised them to steady himself on Katsuki’s hips or belt loops, probably, but before his hands could make contact with Katsuki’s waistband, another pair of larger, wanted hands stopped them, enclosing them in their grip. Izuku looked up from where he’d been focused on landing his palms to balance himself— he was quite dizzy, still— to see Katsuki staring down at him with warring emotions on his face, pleased to concerned to smug to angry, confused and hopeful and distracted.
“Did you kneel when that other alpha said to?” Katsuki clarified, furious growl so powerful it dotted his words, but Izuku could understand him just fine. He looked so on edge, so conflicted, so Izuku hurried to console him, shaking his head plainly.
“Of course not, Kacchan,” he said, head momentarily clearing enough to answer, but forgetting he was on his knees. “Why would I listen to him?”
Katsuki’s shoulders untensed, his scent pumping out another wave of pleased-good-mine, and Izuku surely answered with his own happy scent in response, because Katsuki’s face relaxed fully. It took on a devilish filter, his eyes glinting.
“That’s right. Because you’re mine, aren’t you?” Katsuki hummed, malicious and sure, but there was a hint of relief underlying the arrogance in his eyes, and it was this that woke Izuku up enough to answer wholeheartedly, his inner instinct and greater self speaking as one.
“Yours, Kacchan,” he whispered, and Katsuki pulled him up with both hands still wrapped around his smaller ones, palms to the back of Izuku’s hands, up so Izuku stood on his own feet again; but Katsuki didn’t let go, pulling his hands into the space above Katsuki’s shoulders, pulling Izuku along with them. They were so close, so close, their faces nearly touching. Izuku shivered helplessly as their closeness had their lips brushing accidentally, his gaze drawn to Kacchan’s lips to his eyes and back, Katsuki’s gaze hot on his face, soft breaths puffing against Izuku’s mouth. His hot grasp trailed downfrom Izuku’s hands to his wrists, where they were limp above Katsuki’s shoulders, his touch still so hot, so welcoming. Katsuki’s fingers slid to circle his wristbones, never once leaving his skin, squeezing ever so lightly, thumbs brushing Izuku’s pulse slowly. Slowly, like he could calm the rushing blood himself, and Izuku knew in his soul that even the cells in his veins would follow if Katsuki asked it of him.
He was scenting his wrist glands, Izuku realized, unconsciously, and the thought sent a jolt of something vibrant down his core, liquid heat pooling, as Katsuki stared down at him with an unfaltering warm gaze while he, absent-mindedly, scented his wrists. Like he owned him, like they owned each other, the way mated couples met gazes lovingly, casually, as they scented each other out of habit, without thinking— as natural as the setting sun.
And here was Katsuki, mindlessly rubbing off the scent of someone else from Izuku’s pulse, replacing it with his own, without a thought. Just instincts, Izuku’s teariest side cried, but could it be? Izuku had never considered it before, but the way Kacchan was looking at him right now, like he was the only thing worth looking at in the entire world, like he physically couldn’t look away — the inner self Izuku was beginning to recognize as his omega was rolling around in glee, purring up a storm, nuzzling against its walls like a spoiled cat.
Izuku’s head felt impossibly clear all of a sudden, all the fuzz gone and replaced with clarity. He leaned back the slightest amount, darting his gaze between Kacchan’s eyes, trying to read him, and for once every layer of Katsuki was bared for him to peruse. He gasped at what he saw, heart jumping.
Katsuki knew what Izuku had found, had laid it out for him himself, had let it pour through every pore for so long but finally let it shine through his eyes, as well, the one place Izuku needed to really see.
Izuku looked at him, not even daring to smile in his exhilaration, not looking away, awed and certain his scent was revealing it, happier than he’d ever been in his entire life, vibrating on the edge of something greater than anything either of them had ever known. Katsuki looked back, their lips brushing again.
“Izuku,” Kacchan breathed out on a whisper, like the name held all the meaning in the world. He leaned in, and Izuku went to nod, but Katsuki was already kissing him breathlessly.
Fuck, but Kacchan’s mouth was so hot. Katsuki kissed him as if he were biting into a peach, every movement slow and wet and savoured. Like Izuku was delectable, precious. Izuku matched him movement for movement, even if Katsuki took the lead, the way Izuku wanted him to. Katsuki’s hands came up to cradle his cheeks as he kissed him deep and slow. Izuku let out a swooning sigh that edged on a moan, and Katsuki pressed closer, rumbling from deep in his chest, kissing him wildly.
Kacchan was practically devouring him, honestly, tongue filling his mouth, palms gripping his cheeks. One thumb shifted to press at his chin and open his jaw wider. Izuku melted under him, held up by Katsuki’s hold alone until the alpha pressed him back gently so the wall behind him bore some of his weight. He was probably making whimpering, whorish noises, but he didn’t know, couldn’t hear above the ringing in his ears and Kacchan’s mouth on his, his scent so close and so alive.
Izuku couldn’t really breathe but he didn’t mind, honestly, and the way Katsuki’s hands were sliding around to cradle the dip of his skull from both sides was stealing his breath anyway.
It was like trivial cares like oxygen were far, far detached from the plane Izuku had ascended to, where he could eat, drink, and breathe Kacchan and be satiated, healthy, in perfect form. Something was beginning to settle in him, some collection of pieces that rustled restlessly in the background when he and Kacchan were apart, calmed when they were together, but had never quite laid content. But they were inching together now, begging to click, almost there, and Izuku was so warmed by it, by this rightness, this goodness welling up inside of him.
Something clicked in Izuku’s brain, an old forgotten memory, and Izuku gasped, pulling away. Kacchan chased his lips with lidded eyes, actually whined, and the sight and sound were nearly enough for Izuku to throw every thought he’d ever had away and give himself up wholly to this alpha.
His alpha.
“Kacchan,” Izuku panted, out of breath from the intense making out and his thrilling discovery. He held Katsuki away by the shoulders, collecting himself.
Katsuki grunted, pouting a little and not looking away from Izuku’s lips. Izuku would take it.
“The doctor said we imprinted on each other, Kacchan,” Izuku reminded him, practically vibrating.
“‘S’at even mean?” Katsuki grumbled automatically. Their parents wouldn’t tell them what the doctor had said that day after shooing little Izuku and Katsuki out of the room with a nurse and staying back to speak in hushed tones with the secondary-gender specialist. There wasn’t much literature on imprinting — it was all hush-hush, for some reason, nothing helpful in books or on the internet that Izuku could find, nothing they could weasel out of their tight-lipped parents on the subject.
“Kacchan,” Izuku tried, giggling as Katsuki held his wrists hostage and ducked in to pepper kisses across his neck and face.
“Kacchan, what if — haha — what if we — KaCCHAN — what if we’re already bonded?” Izuku managed, breathlessly.
The world tilted on its axis and stopped.
Or at the very least, Katsuki did, pulling up short and staring.
“What?” He whispered, hesitant.
Izuku caught his breath, eyes wide, the sun shining through his face.
“It all— everything adds up, if you consider that.”
Katsuki thought about his intrinsic, unshakeable need to be with Izuku some — no, most — of the time, the way his alpha claws at him from inside when they’re apart, how even when they’re together there’s an aching need for more, more, more.
He thought about Izuku resisting the pull of an Alpha Command, then listening to his suggestions without hesitation in contrast, how they could smell each other but not so much other people unless they tried. How Izuku’s scent was the single best sensation in the entire world.
Katsuki looked at the hands in his, so utterly precious to him, how he’d watched them grow alongside his their entire lives, needed them on him for the full length of that time, needed Izuku close like a second skin, missed him like a missing limb.
It wasn’t quite normal, was it, for Izuku to burrow into him as if attempting to nestle beside his pulse, restless without him, colours brighter for them both when the other was near.
Codependency, his mom had laughed, once, but was that all it was?
Or rather, was that all it could be? Katsuki didn’t know the first thing about imprinting, only that they’d been warned against it, that they’d done it anyway, that it attributed to how Katsuki’s blood sang whenever he saw Izuku’s fluffy head.
“I think imprinting means…” Izuku started, blushing and shy but strong, the way he’d always been, “I think it means you’ve.” He blushed harder, blinking rapidly, “You’ve ruined me for anyone else, Kacchan.”
Katsuki’s heart stuttered.
“And… and I did for you, too.”
Katsuki liked the sound of that. He really, really liked the sound of that.
“Ruined you,” he mused. They were standing a more respectable distance apart now, after Izuku had held him there, now connected only by their hands hanging clasped between them.
“For anyone else,” he continued, starting to grin, and Izuku looked up at him with hearts in his eyes, excited, the image superimposed by every Izuku he’d ever known, every year of their lives, that same expression gifted to him freely, as if out of everyone, he deserved it most.
In the end, it was as simple as that. Katsuki was Izuku’s and Izuku was Katsuki’s, and that was a fact as certain as the stars in the sky, just as simple and known and grand.
But bonded. That lit a fire in Katsuki’s deepest core, even the thought of being bonded to Izuku, married, mates. The most damning of all their archaic gestures, the deepest commitment, the most symbolic.
To be bonded is to truly be owned. And Izuku thought they already were.
“You’re mine.” Katsuki repeated for the umpteenth time, rolling it over his tongue, finally believing it, finally feeling it. Izuku blushed heavily, nodding, leaning forward like he couldn’t help it.
But Katsuki wasn’t done.
“And I’m… I’m yours.” Katsuki said, definitively.
Izuku’s eyes widened, and he appeared to have stopped breathing, brain offline. Katsuki poked his forehead and he swayed, then blinked rapidly, dashing forward with a hushed, awed “Kacchan,” to bury his face in Katsuki’s chest, wrapping his arms around him. Katsuki hugged Izuku back tightly, scent surely pleased, and Izuku responded with the freshest jasmine and magnolia, warm welcoming earth, as sure as their embrace.