Chapter Text
"And he's an omega?" Inko coos, rubbing her fingertip across the little bundled baby in her arms. "How pretty."
"How lucky, you mean," Mitsuki retorts, from her bed. She's surrounded with thick blankets and soft pillows, tired after childbirth but no less lively than usual. Masaru sweeps hair from her forehead from where he sits beside her. "My clan couldn't withstand another alpha heir, five generations in a row."
Inko smiles up at Toshinori, who places a gentle hand against her back as he bends to view the new addition to their family.
"He's got Mitsuki's eyes."
Inko hums in agreement, shifting the baby blanket back so that she can smooth out the little tuft of blonde hair beneath it. "And her hair."
"And my everything," Mitsuki boasts.
Masaru chuckles beside her, but nods nonetheless. "He'll be just as amazing as you are."
Izuku peeks at them all from where he's creaked open the door, hiding himself behind the thick oak wood.
Even from afar, he can see that they aren't lying. The little baby has brilliant red eyes and soft looking skin and a scowl on his face to match the one that his mother is sporting not a foot away as she switches positions with her husband so that she can be the big spoon.
He's just started to sneak back out of the room to give them their privacy again when the baby starts fussing.
He twists and kicks in Inko's hold, not so much as to get away but instead just to be finicky. He screws his face into a pout, and Izuku can't help the fond smile that grows on his own lips as he watches. Already, he has such a strong personality. Izuku wants to be friends with him.
Inko shifts so that the new baby is on her shoulder, patting his back with gentle fingers. His chubby cheeks squish against her shoulders.
The new position makes it so that he and Izuku are now perfectly face to face.
The baby blinks a few times, almost immediately calming when he sees Izuku staring at him. Their parents quickly get distracted, but Izuku doesn't bother with eavesdropping on their conversation.
Izuku tilts his head and the baby blinks at him again. Then frowns at him, as if Izuku was getting on his nerves.
He can't help but quietly snicker at that, but enamored affection quickly grows in his chest the longer he stares at the newborn. Izuku can't wait to get to know him.
He lifts his hand to shyly wave, and the baby huffs. He squeezes his eyes shut petulantly, but they quickly open again as if to check if Izuku is still there.
Inko laughs at something Masaru says after, but Izuku is more focused on his soon-to-be friend. There aren't many kids in their house these days— or ever, before his parents had him.
And though Izuku has been to parks or arcades (always strictly guarded with no less than three men hidden in shadows), none of them had mattered so much so fast as this one. He hasn't even touched him and Izuku already knows he'll give this little baby the world if he should ask for it.
Inko turns towards the window, inadvertently breaking their eye contact. Izuku stands on the tips of his toes to try to get it back.
The sudden shift in motion makes the heavy door slide open, though, and Izuku stumbles forward into the room.
Inko and Masaru startle, but Mitsuki snorts and rolls over to gesture him in. "Took you long enough, kid. C'mere."
"I'm— sorry to interrupt!" he yelps, nervously clutching his hands behind his back. All of the underlings in their clan do the same pose when his parents and the Bakugous walk down the hall, so it only makes sense to do the same now.
Toshinori lifts a placating hand, bending on one knee to reach his eye level. "No need to be so formal with family. Did you want to see the baby?"
Izuku takes a hesitant step in. And, when they don't get upset at him for it, drops his stance and steps in further.
"I… just wanted to see if Auntie was alright after her hospital visit."
Toshinori ruffles his hair once he gets close, standing up. "You're a good kid, Izuku."
Mitsuki grunts, fitting her arm beneath herself as Inko and Toshinori wander closer. "Please. Those bastards know better than to let me die in some rinky-dink hospital. Least of all from childbirth. I'd haunt their asses down to the next fifty generations."
"Rest, dear," Masaru huffs. He urges her to lay flat again, and Mitsuki goes willingly with an exaggerated roll of her eyes and a small smile in his direction.
Inko has made her way over to the large bed in the middle of the room. It was so large that the two occupants in it don't even have to make room for her as she sits on the edge, smoothing out the blanket as she goes.
"Izuku," Inko calls, softly. "Come sit."
Inko pats the spot on the bed beside her, and Izuku scrambles to follow and climb up. It's too tall for him, though, and Toshinori lifts him by the waist to help.
As soon as Izuku claws his way to his mother's side, he plants himself directly against her upper arm so that he can stare in the baby's face directly.
The baby is already waiting to meet his gaze, the red eyes sparkling with curiosity.
"Meet Katsuki. The next omega heir of the Bakugou Clan."
"Omega?"
Izuku is an alpha. His parents have always told him that no alpha is complete without an omega, no matter who they are.
Izuku reaches out, and Inko tilts her arms so that Izuku can press his own chubby fingers against the baby's— against Katsuki's face. His cheeks are as soft as they look, and Katsuki grunts at him when they make contact.
"He's pretty," Izuku breathes. "Like a dove."
Inko laughs as he brings his other hand up to squish Katsuki's cheeks, and Katsuki glares at him for that, too. Although Izuku isn't sure if it's from the nickname, or from the touch.
"Let him hold the brat," Mitsuki offers. "Might as well let them get to know one another."
"Can I…?" Izuku asks, tentatively.
"Hold your arms out like this…"
Inko switches Katsuki to one arm, positioning Izuku in the best way to hold the newborn. He holds the pose rigidly, straightening his spine as Inko stands to transfer Katsuki into his arms.
"And make sure you keep his neck supported like this, or else he'll be hurt."
Inko tucks the blanket in the empty spaces between Izuku's body and Katsuki's swaddled form, and then takes a step back.
Izuku feels as if he'd just been gifted physical starlight.
The weight of Katsuki in his arms centers him in a way that nothing else has. He would do anything for him.
Izuku tightens his hold, firm so that Katsuki can doze off peacefully without any fear. He doesn't look away for a moment even as Katsuki is quick to nod off and gently snore in his arms.
"I'll take care of you," he promises, quiet. For Kacchan's ears only. "Forever, okay?"
He doesn't notice when Inko settles on the other side of the bed, sharing a knowing look with Mitsuki where she lays.
"That sure was easy," Mitsuki says, breathing a laugh.
Masaru, snuggled up in front of her, passes her a glass of water. She frowns up at the babying, but accepts it with yet another roll of her eyes. "That just means the marriage won't be an issue for them in the future.”
"Must be fate," Inko agrees.
Toshinori joins her, keeping a careful eye just in case Izuku needs to reposition his arms better. But there's no need to worry, they all can see.
"Izuku will take good care of him."
---
The two most influential Yakuza families in Japan are the Yagis and the Bakugous. It's a well known fact that they're close enough to practically be considered one clan, even.
Yagi Izuku, son of Yagi Toshinori and Midoriya Inko, is ten years old when he's betrothed to Bakugou Katsuki, newborn omega son of Bakugou Mitsuki and Bakugou Masaru. A marriage to officially combine the two families.
Katsuki is ten by the time Izuku becomes the new acting leader of the Yagi clan.
"Oi, Deku. Come play with me!"
Katsuki kicks open the engraved door to Izuku's, formerly Toshinori's office. Much of the furniture has been moved, to be replaced now that someone new is taking over. Izuku had to insist to his mom that they atleast keep the desk the same.
He's sitting there now as Katsuki rushes over, head in his palms until he realizes that it's his Kacchan calling for him.
He sits up straight as Katsuki hops up onto the desk, kicking his legs.
"Play with me," he orders again, as if the entire hall hadn't heard the command.
"I can't right now, Kacchan," Izuku says with a tired smile. "I've got to sort through some matters that dad— I mean… that Yagi-san can't anymore."
Toshinori had fallen ill a few years ago. The doctors say it was inevitable with how ragged he ran himself for most of his life, but he'd still be able to live long if he took it extremely easy for the rest of his days.
Izuku was happy to take the mantle from him, even if it was too early, if it meant he got to keep both his parents for a little while longer.
But ever since he'd had to take on his new duties, Katsuki felt… well… ignored. As if he came second, now.
And Katsuki is number one at everything he does. Stupid Deku.
"I'll see you after lunch, alright?"
Katsuki grumbles as Izuku disregards him for a moment to turn towards an underling that opens up a laptop for him.
He reads through whatever document is on screen, and the longer he sits there not paying attention to Katsuki, the more irritated Katsuki gets.
He huffs, crossing his arms and puffing out his cheeks. He kicks his legs up on the desk, even though he knows Izuku hates that, and ignores when another underling bows and asks if he'd like something to eat.
"Leave me alone," he grumbles, and the underling immediately stands back in line. A line of Yakuza were bordering the walls on all sides except directly behind the desk, as always. While Katsuki and Izuku were used to having that many eyes looking after them, it had upped exponentially ever since Izuku became the new leader.
Another thing to irritate Katsuki.
"Deku," he huffs, though it comes out more like a whine.
"Yagi-sama," a Yakuza calls from the doorway. The new title makes Izuku flinch. "The Nishito clan leader has arrived."
"Ah… everyone's here already?"
Izuku quickly shoots off a few emails with the laptop still shoved in his face, and then stands.
The Yakuza nearest to him straighten up, ready to follow their new leader to his next meeting.
Katsuki perks up when Izuku passes in front of him, but all he gets is a gentle pet against his cheek, Izuku's warm fingers ghosting lower towards his scent gland before they leave him with just the barest brush.
Then Izuku heads towards the door, instead of giving Katsuki more attention.
"Don't put your feet on the table, Kacchan," Izuku mumbles distractedly as he fixes his tie in a nearby mirror.
"You're not the boss of me, Yagi-sama," Katsuki bites back.
Izuku flinches harder than he did before, and Katsuki only feels mildly guilty about it. Instead of immediately apologizing, though, he just ducks his head down and continues pouting.
Katsuki hears Izuku sigh, and turns away so that he's facing the corner instead of him.
"Kacchan…"
That same underling at the door hesitantly speaks up, "Sir, they're—"
"Everyone's dismissed," Izuku interrupts. "If they start getting antsy, tell them I'll be there in less than five minutes. Got it?"
"Yes, boss."
In almost the blink of an eye, all but Izuku and Katsuki have left the room.
Izuku fiddles with his tie for two seconds more, before he turns back towards the omega. Katsuki huffs as he feels Izuku's eyes on him. It's heavy, almost, and it makes Katsuki feel tiny in comparison. Not even in a bad way.
Izuku slides next to him, placing his palms flat on the desk on either side of Katsuki's body. Still, he has to lean down a bit to get eye-to-eye with him.
"Have I ignored you too much today, Kacchan?"
"Yes. You always ignore me when you have stupid meetings to go to."
"I'm sorry, Kacchan. You know… soon, you'll be at these meetings with me. Then you'll see that I haven't been having any fun without you."
"I don't care if you're having fun without me…" Katsuki grumbles.
Then his lower lip wobbles, and unbidden tears begin to well up against his lower lashes. "I just want to be there with you. Wherever you go."
"Oh, Kacchan…"
Izuku tilts Katsuki's head up as it starts to lower, keeping that eye contact. "I want to be with you too, Kacchan. Always."
Izuku is so much taller than him, ten years his senior. Katsuki hasn't reached puberty yet or anything, but he still feels so small in comparison as Izuku leans forward and presses their foreheads together.
Katsuki's eyes flutter shut, accidentally dripping the tears from his lashes and making them soak into Izuku's sleeve.
"But right now, I have to go. I'm doing these things for both of us— and for everyone following our families. It won't be forever, and then we can play again. Alright?"
When Katsuki stubbornly doesn't respond, Izuku lifts up to press a gentle kiss to his forehead. Katsuki's shoulders drop, resigned, and Izuku places his palms on both to massage them with his thumbs.
"I'll be back as soon as I can. I promise."
"Yeah, yeah," Katsuki grumbles. "I know…"
Izuku opens his mouth like he wants to say more, or at least to comfort Katsuki until he stops crying.
Instead, he's interrupted by a firmer knock on the door.
"Izuku. Everyone's waiting."
Inko's voice cuts through them, and Izuku sighs loudly through his nose as he stands up straight again. She isn't one he can send away, even if this wasn't an important meeting.
"I…" Izuku sighs again, and rubs his hand across his face. "I have to go Kacchan."
He steps backwards towards the door, eyes on Katsuki the entire time. Even though Katsuki just resolutely glares at the ground, his arms crossing tighter and tighter at his chest the further Izuku gets away, Izuku watches him.
He turns away when he reaches the door, and doesn't look back after.
That day, Katsuki has to play by himself until the sun has long set. He doesn't see Izuku until that next morning, who lets him sit in his lap during breakfast and spends the entire morning doing nothing but holding him, to make up for having to let him go.
Still, it isn't enough for Katsuki.
---
A few weeks later Katsuki bursts into their largest office, head held high even when dozens of head whip over to him. He doesn't recognize any of the faces until he finds Izuku, at the very back of the room sitting at the head of the long, ovular table.
So Katsuki ignores the extras as he stomps over, followed closely behind by the men who protect him day-to-night.
And he stops, right beside the person sitting next to his Deku on his right side. Katsuki puts his hands on his hips to puff out his chest and, with all the confidence only he can muster, clicks his tongue.
"That's my chair," Katsuki says haughtily, as if he's three feet taller than he actually is. There's a few chuckles in the background, but Katsuki ignores it. He didn't stutter, after all. That's his spot.
The unamused clan leader glances up at Izuku, as if waiting for him to shoo Kacchan off.
Instead, Izuku waves his hand in dismissal. Already, his underlings are setting up another chair on the opposite end of the table for them. They have no choice but to move.
Katsuki scrambles onto the chair, planting his palms flat against the thick wood as he fits his legs underneath himself to add a bit of height.
"Kacchan," Izuku admonishes, though it's entirely dampened by the soft way he smiles at the young omega.
Katsuki huffs at him, sitting up straight. Though he's rather tiny in the chair he's stolen for himself, his mere presence (not to mention the way he arrived) is enough to garner the attention of everyone else.
Izuku waits until he's settled himself before he turns back to the rest of the clan heads.
"Now, where were we?"
If anyone has a problem with Kacchan being there, they keep their mouths shut for now. The Yagis were still the most powerful clan, whether they liked the new leader or not.
Nishito-san, leader of his clan (and the one whose chair Kacchan usurped) frowns. His family is rising in prominence, but has been… 'low-ranking', so to speak, for many years before now.
He looks right at Katsuki as he speaks,
"There are… more than a few of us who worry about the direction our organization is headed. Though we are not one group, but many formed as a family, we feel there's been… encroachment happening."
"The Todoroki's, for example," one leader snorts under their breath. "They think they're too good to be with us. They've completely taken over our side of town."
A few people grunt in agreement. Izuku stays quiet as they begin debating amongst themselves, and Katsuki watches as he leans back in his chair to not participate but instead to watch how everyone interacts.
Katsuki mimics him and does the same.
"Soon, our clan will be so small that we may as well pray we're lucky enough to marry into one of your families," someone grumbles.
"Oh, you wish you were great enough for that honor," another nobody hisses back. "You're only here because you've been in this organization from the beginning. You don't bring anything to the table."
"— Let's calm down," Izuku cuts in, suddenly. "tensions are high because of these new changes. There is no need for in-fighting."
Katsuki nods his head along with him, jumping up in his seat. "Yeah! You guys sound like a bunch of babies on the playground."
There's a sudden hush as his words register. His voice is higher pitched than everyone else's, and cuts through the bickering sharp like a knife.
Every eye turns from him, to Izuku.
And when Izuku does nothing to admonish the little pre-teen, they hesitantly turn towards one another instead.
One voice, however, speaks up.
"And why exactly is this grade schooler allowed to lecture adults in this matter?" Nishito sneers. "Surely he has a crayon box he needs to get back to."
Katsuki huffs, slapping his hands down on the table to immediately argue his case. They do fuckin' sound like a bunch of babies arguing over who gets the last lollipop.
Ever since he was little, Katsuki has been taught by his mom and dad that the Yakuza are strongest together and that it's okay to argue sometimes, but they have to come together at the end of the day or else everything will break and fall apart.
And if he learned that before he even finished elementary school… they had a lot more growing up to do than he did, thank you very much.
Still, he's interrupted by Izuku's hand raising to usher him back down in his chair.
"Careful, Kacchan," he murmurs softly. "Your socks will slip on the wood. Why don't you come sit with me, instead?"
And, immediately, any urge to fight flies out the window as Katsuki hops off the chair to instead scamper into Izuku's lap. It'd been so long since they last cuddled and scented— maybe the meeting will be over soon so they can go watch superheroes together.
The clans shift uneasily as they wait for Katsuki to settle down at his new perch, his chin just barely able to rest against the tablehead.
Izuku holds him firm so that he won't slip, and nudges the scent gland on his wrist against Katsuki's neck. To keep him calm and happy.
As soon as Katsuki lets out a childish, pleased purr from deep in his chest, Izuku smiles.
Then, he turns to address the room.
"In case you hadn't realized, this is Katsuki of the Bakugou clan, and he can come and go wherever he pleases, Nishito-san. You will do well to respect your betters."
If the room had been silent before, it was deafened now. Not even the soft sound of breathing could be heard.
Katsuki never realized that Izuku's voice could turn that icy-cold before. Not even when Katsuki stole his last piece of katsudon from his plate had he ever heard it like that.
"I will respect no child that doesn't know what he's talking about."
Someone on the opposite side of the table hisses. Katsuki recognizes them as an old friend of the family's, someone who has always been around. In comparison, Nishito's face is relatively new.
Therefore, Katsuki doesn't give two shits about his opinion.
Still, he stays silent because Izuku clamps his hands down on his sides and holds him firmly as he stands up.
"Then we have a problem."
Izuku begins to set Katsuki down, and a few of the other Yakuza back out of their seats and away from the table.
When Katsuki squints at them, he recognizes them all as old, familiar faces. The ones who don't seem to have those same self-preservation skills are all new.
And while Katsuki enjoys a good squabble as much as the next person, he could tell that Izuku was getting mad.
He didn't like it when Izuku's friendly face glared like that, his bright eyes turned dark and dull as they glare at the offending party.
Nishito is glaring right back, and Katsuki's hackles raise when Izuku's scent shifts.
It's acrid, like smoke, and it burns his nose when he gets the full brunt of it with how close he is to Izuku.
"Yagi-san…" An underling speaks up behind him.
Katsuki kicks his legs to catch Izuku's attention, before he's set on the floor again. Izuku hesitates, and Katsuki tugs on his arms to get him to lift him up again.
"Deku," he orders, much sharper than the underling. "Pay attention to me."
Izuku's breaks eye contact with Nishito, who falls back in his seat with an exasperated huff. Izuku obediently lifts Katsuki up, letting him rest against his hip before he demurely settles back in his seat.
As soon as he does, letting Katsuki find his footing in his lap again, he lifts his hands to placate his men, whose fingers had inched closer and closer to their weapons the longer the glaring match had gone on.
Izuku takes a deep breath in to calm himself, which stutters in his chest when Katsuki shoves his wrist against his nose. Just like Izuku had done to him earlier.
"Scent me," he orders again, quieter so that it would just be for him to hear. "I don't like when you yell."
Izuku's eyes flutter shut as the omega scent both clouds and clears his head. Kacchan had always been able to play him like a toy, but he couldn't resist when the omega could be so sweet to him like with moments such as this.
"Of course, Kacchan," Izuku says softly. "I'm sorry."
He leans back so that he can let Katsuki rest more comfortably in his lap now that they are facing one another. Katsuki's legs end up outlining his on either side, his legs so tiny that they barely reach past the seat of the chair.
As he gets himself situated, Izuku turns to address the room.
"As you can see… fighting gets us nowhere. We have a responsibility to our clans— all of our clans, even those who don't belong in our group— to do things right. If you have any issues with outside clans, then we will deal with those as best we can. But we don't need to add more conflict on top of that."
Izuku eyes Nishito, who only glares at the table.
"And if anyone has a problem with anyone inside of our group… deal with it yourselves. Or I will have to. I understand many of you think that I won't be able to fill the shoes left behind for me after my father's illness…"
Izuku pauses, mulling over his words carefully.
"The one thing you need to realize is that I will do anything for this family. I will not let his legacy be ruined, no matter what I have to do. Is that understood?"
There's an underlying threat that Katsuki can't really parse. But the tone alone has him hesitantly nodding along with the others, even if the words aren't meant for him.
And for those 'others', who understand completely the threatening words coming from the head of the Yagi clan… they keep their mouths obediently shut and make no eye contact. To become enemies with him would be a quick and dishonorable death. A quiet one, even— one swept under the rug to be promptly ignored and never to be brought up again.
Nishito doesn't say a word about Katsuki after that.
---
The room clears hurriedly after the meeting ends, and Katsuki sits in Izuku's lap the entire while.
Inko is the last to leave, looking oddly proud as she gives Izuku a brief nod before she follows the last person out. Katsuki hadn't even noticed she was in the room with them until she handed her phone to Nishito, some random person Katsuki didn't care about on the other end.
Nishito had paled, bowing at her before he stood and exited the room, hurried apologies on his tongue as he apologized to Toshinori himself on the other line.
Katsuki knew that Deku's dad was on strict bed rest and didn't need the extra stress of clan business. Which means he's gonna be in a lot of trouble for messing up his peace of mind.
Good. Katsuki finds a vindictive peace, knowing that he'd get what's coming to him some way or another.
But that didn't matter at the moment. Right now, the room was entirely empty save for him and Izuku. It's just the two of them, finally in private.
Izuku is still calming down a bit, head tilted back against his chair as his scent finally loses that nasty, anger-tinge that stubbornly clings to the wisps of it.
Katsuki nuzzles him, to encourage his natural scent to come back faster. It was earthy, kind of grassy, and was one of Katsuki's most favorite things in the world.
Izuku peeks down at him, offering him a tentative smile when he notices Katsuki already staring.
"I'm sorry about that, Kacchan. I shouldn't have lost my cool around you."
Katsuki huffs haughtily, hugging his arms around Izuku's neck so that he can scent against his chin, dangerously close to his neck. Katsuki's mom had always told him that no one should scent his neck if they aren't family or if they aren't someone he really loves. Romantically loves, or whatever.
She'd also said… "Don't let these shitty extras get to you. They have to listen to us 'cause we lead them and we know what's best."
Izuku laughs, scrubbing his hand across his face before he gives Katsuki a smile.
"You're right, Kacchan. But we have to listen to them back— so that we know what they need to succeed. Sometimes, though, that means they want to… step on our toes."
Katsuki leans back so that he can stretch his legs and wiggle his toes in his socks.
The action makes Izuku burst out laughing as he supports Katsuki with one hand planted near the base of his spine. It's so large that it reaches from side to side. He could probably lift Katsuki just like that.
It makes him blush, oddly excited at the prospect.
"Yeah, well… we don't need any of them," he says grumpily. "Not right now anyway. So just pay attention to me now, okay?"
"Of course, Kacchan," Izuku gives in easily, leaning down to butt their noses together and give him a butterfly kiss. "I'll always take care of you, won't I?"
Katsuki nods smugly, because he knew that there was nothing more true.
He scents along Izuku's neck, and lets Izuku press their lips together in something far more chaste than he really wanted deep inside.
But it was his first kiss, so it was perfect nonetheless.
---
Long before that moment in the office, Katsuki knew that Izuku always calmed down when he scented him a little.
Even if he was really angry, he would accept Katsuki's puppy eyes and the offered wrist. Or, rarely, Katsuki would tilt his head and bare his neck up towards the alpha, so that his untouched gland meant for mating bites would be perfectly visible for him to see.
Izuku would always bury his face against it and breathe in deep, murmuring a soft, "Sorry for yelling, Kacchan."
Even if Katsuki didn't actually mind the yelling that much— because Izuku never yelled at him— he would always gently apologize and eagerly accept the omega's scent clinging to him like a second skin. It would mix with his own alpha scent and make Katsuki feel all… squirmy inside to know that Deku was walking around smelling like him.
Katsuki loved it.
And when both of their parents noticed, they didn't even fuss. They just gave Izuku this weird, knowing look and a grin with all teeth.
His mom would playfully tease him, blinking her eyes innocently when Katsuki would frown up as she attempted to scent Izuku too, wrist to wrist.
What little scent that would transfer over wouldn't at all be enough to overpower what Katsuki had doused Izuku in, but it would still make him pout and huff until Izuku would kneel down to his height and let Katsuki cling to his neck so that he could scent him all over again.
Izuku would always get blushy and stuttery when Katsuki's mom would guffaw at him as he scuttled down the hall with Katsuki in his arms.
Katsuki didn't realize until a bit later in life that he'd been flirting with the alpha that entire time, staking his claim on him before he'd even known what it meant.
---
A few years later, Katsuki goes through his first heat.
---
Katsuki had been feeling a bit 'off' all day. He'd bared his teeth a lot lately, the gums above his canines aching to bite down on something, it seemed. And he'd been… not itchy, but close? It was like the clothes touching his skin were touching him wrong today.
But he'd dealt with it, because all in all it was a normal day. Katsuki walks with his friends past the gates of their middle school, tugging at the tie of his uniform as soon as he's past the boundaries.
The security just outside of it nods at them in acknowledgement, but Katsuki ignores it in favor of growling at Kaminari as he hooks his arm around Katsuki's neck and tugs him in close.
"Wanna come over to my house tonight? I just bought a new game and—"
Katsuki shoves him off, partially because he'd pressed right up against his sensitive scent gland— which had been aching all day. "Don't you have a lot of homework to do, dummy? You skipped out last week."
"I was sick!" Kaminari whines. "And that means I get to relax until I have to dive back into studying."
"I think that's the other way around, dude," Kirishima laughs.
Katsuki would've responded with a quip of his own if not for the way a cool burst of wind flows against him and makes him realize that he's broken out into a sweat at some point. Which was strange because they'd only just started walking home, at a leisurely pace even.
Maybe he was getting sick?
Katsuki grunts as his friends start a friendly argument about the best play-study balance, and falls behind the group of them. Mina gives him a curious glance, but he waves her off as he instead pats around his pockets for his phone.
He places an idle hand on his belly as a… funny feeling settles in it. He doesn't know how to describe it other than something squirmy rolling around inside, leaving a wake of heat behind.
Oh. His heat.
Katsuki frowns down at himself, his steps faltering as he tries to squint at his belly from the outside in. Was this his heat? He hadn't had one yet… but his parents warned him it'd probably be time soon.
He was supposed to go to the nurse when it happened, but would it be worth it to turn back when he was already on the road towards home anyway? How bad could his heat hit him in the time it took to get to his front door?
Katsuki nervously wrings the sleeve of his jacket as he stares down at his phone, idly scrolling through the contacts list.
"You okay, Bakugou?"
Kirishima had dropped back to join him in his much slower walking pace, and Katsuki shrugs his shoulders half-heartedly.
"I need to call Deku," he murmurs. "Go home without me today."
Kirishima raises both his eyebrows, hooking his fingers around Katsuki's bicep to pull him to a stop.
"Are you feeling sick? We can wait with you until he gets here."
Kirishima's nose twitches as he scents the air around Katsuki, and a strange expression passes by his face. His eyebrows scrunch up, confused, and he dips in closer for another smell when Katsuki waves him off.
With a click of his tongue, Katsuki presses his phone to his ear and shoos Kirishima out of his personal space. "I'm fine, Shitty Hair. Just… gimme a minute."
Kaminari, Sero, and Mina notice the two of them stopped, and the three of them shuffle over to rejoin their half of the group. Katsuki lets out a shaky breath as he leans against a nearby wall and slides down it, his legs uncharacteristically shaky as he does so.
He clicks 'call' before his friends can start worrying over him, and places his other hand over his free ear to block out the rest of the ambiance. There were a few other groups of kids walking home who pass them by, and a handful of cars driving down the nearby street.
Each new noise makes him jumpy, and Katsuki has a feeling it's his heat making him act like this. He's tense all over, growing more and more anxious with each ring that passes without hearing Izuku's voice on the other end.
Katsuki has just buried his face against his knees, his head swimming and his breath coming out heavy, when Izuku picks up.
"Kacchan? Did you want me to come pick you up today?"
"My heat's coming," Katsuki says in a rush. "Everything feels funny."
There's a pause on the other end, and Katsuki gets distracted by the sudden worried outbursts his friends make above his head.
"I'll be there as soon as I can, Kacchan," Izuku says. "Wait for me in the school, alright?"
Katsuki whimpers, and Kirishima shifts beside him. He drops down into a squat, his eyes narrowed as he leans in close again, and Katsuki glares back.
"We're already outside of it, and I…" Katsuki pauses, squeezing his legs tighter to his body "I don't think I can.. move. My legs feel so heavy, Deku."
Izuku sighs, or maybe just inhales sharply? Katsuki can't really tell because all at once, Kirishima is back in his face again.
His eyes are cloudy and half-lidded, and with how close they are, Katsuki can see that his pupils have dilated alarmingly wide.
"Kirishima— get the hell away from me," Katsuki huffs. "I'm on the phone."
"Omega," Kirishima responds, planting his palms against Katsuki's shoulders and holding him flat against the wall they were tucked against. "Smell so good."
Kirishima nuzzles his face against Katsuki's neck, and he yelps when he feels a brush of bare fangs against his swollen scent gland.
"Kiri—!" He cries out, only mildly embarrassed by the panic tone. He slaps a hand over his gland, shoving at Kirishima's wrist to try to get him to stop holding him down.
But Kirishima growls at him. A deep, rumbly growl that makes Katsuki freeze in place. It wasn't a sound he heard often, not directly towards him anyway, and the omega isn't sure what to do except instinctively submit for his own safety.
His hand falls away, the other still gripping his phone slightly a ways away from his ear.
Deku is still on the line when he presses it back to himself, and Katsuki can make out hurried footsteps and the sound of a car door unlocking.
"D-Deku," Katsuki whimpers. "Kirishima is…"
Kaminari snaps his fingers in front of Kirishima's face, momentarily distracting him, and Katsuki twists away to try to crawl behind him for safety.
There was nothing more dangerous for an omega than to go into heat outside of safety, but even more so for an unmated omega to do so.
Katsuki was an idiot to forget that Kirishima is an alpha. The only alpha in their group, and Katsuki the only omega. The rest were betas, who were ill-equipped to handle the situation. Mina grips Kirishima hard by his shoulders, her painted nails digging into his blazer.
"Kiri, babe. You gotta calm down."
Kirishima growls again.
And then he snaps his jaws when Sero reaches forward to try to physically separate them. He misses by a hair, but the audible sound of his teeth clacking together has Sero looking pale nonetheless.
Katsuki struggles beneath him, pinned as he is.
"Stay," Kirishima barks. "Stay still, omega."
His voice is frighteningly different, each syllable dark and tinted with a hint of a growl. Katsuki hates how it makes him feel small and insignificant like a bug about to be crushed.
But, for once, Katsuki is too scared to try to tell him off. He just wants it to stop, just wants to go home and hide in his nest and not come out until he doesn't feel so out of his element anymore.
Before this, Katsuki would've had so much fun wrestling with Kirishima, alpha or not. They always had a great time messing around during gym. But this Kirishima is different. He doesn't even care about how scared he's making Katsuki feel.
It's frightening the rest of their friends, too, by the way they get more desperate. Kaminari, threat of biting be damned, climbs onto Kirishima's back to fit his arms between him and Katsuki.
Sero attacks from the top, wrapping an arm around Kirishima's shoulders to try and force him back. And Mina swoops against the other side, one palm firm as it presses against Katsuki's shoulder blade— successfully hiding his scent gland from view— and the other painfully digging into Kirishima's wrists to get him to let go.
Katsuki's phone gets knocked out of his hand as all three of them try to haul Kirishima off of him, but he ignores it for the moment to try to escape.
It's useless as Kirishima's fingers dig in tighter to his waist, until it's painful and sure to leave marks. Katsuki lets out a whimper of distress, and he knows his scent follows suit.
It only makes things worse, though. Kirishima responds aptly, shoving the offended bodies off of him with ease before he rounds on Katsuki again and sits up on his knees.
Katsuki hisses, like a frightened cat, as loud as he can when Kirishima leans his body over him again.
"A-alpha!" Katsuki cries out, reaching for his phone again. Izuku is on his way, he just has to hold out until then…!
Kirishima pulls Katsuki away from it, and his hands ache where gravel and dirt dig into them. He can't even kick his legs, because Kirishima pins one between both his own and fits his hands beneath Katsuki, to play with him like a ragdoll.
Kirishima has just flipped Katsuki onto his knees, trying to scruff him with teeth around the back of his neck to keep him from squirming, when Izuku's scent bursts through the chaos.
Katsuki gasps out loud as soon as it hits him, and then again when the heavy body on top of him is ripped away.
In as long as it takes for his vision to clear, Kirishima is being flattened on the sidewalk as Deku growls at him. His arms are pinned behind his back, the leverage keeping him there, and Deku is already snapping his free hand to urge another figure forward.
Katsuki scrambles up onto his knees, momentarily taken out of the center of attention as the rest of their friends hurry to keep Kirishima from trying to buck Deku off.
Although, it looks like he would have a tough time doing so regardless. Katsuki watches as Deku digs his thumb into Kirishima's neck, near his scent gland, and it makes the other alpha hiss angrily.
It's a move meant to draw an alpha's attention defensively rather than offensively. And it works perfectly as Kirishima curls in on himself to protect his neck.
Deku backs off, briefly, his growl raising in volume to keep Kirishima subdued.
"Alpha," Katsuki whines, as his own instincts rise to the call as well. He slumps over in pure relief now that he's safe, and tries to blink away the embarrassing tears. He hates crying in front of his friends.
"Kacchan," Deku rushes to respond. He takes a hesitant step back to make sure Kirishima won't try to pounce, but it seems that Mina's calming hand against his back is keeping him grounded in the moment.
It seems like he's barely holding himself back from tackling the alpha all over again, though. He's gritting his teeth to the point that there's a visible vein from his jaw to his neck, and Katsuki (even with the building heat distracting him and the stress scents surrounding him from all angles) can smell Deku's scent getting sharper. Angrier, the longer he looks at Kirishima.
Katsuki feels his insides flipflop when he realizes it's for him that Deku is nearly going feral.
But they don't need a scene like that here. And Katsuki really just wants Izuku to hold him in his arms and take him home. He just wants to go home with his alpha.
"Izuku," Katsuki calls, reaching a hand out. At the same time, he releases his scent to urge Izuku's attention over. "Alpha…"
Izuku shivers. From head to toe, it's as if the title takes hold of him. Still, he glares at Kirishima as if he wants to take a bite out of him and leave him to bleed out.
But as soon as he realizes that he's still being handled, Izuku glues himself to Katsuki's side. He specifically situates himself between Katsuki and the rest of them, shielding the frightened omega from sight.
His arm drops across Katsuki's shoulders, and everything seems a lot less overwhelming when Izuku's warm scent envelopes him like a safety blanket.
"It's okay, Kacchan. You're safe now, nobody is going to hurt you. You did everything right."
Izuku soothes him both with words and his scent as his arms wrap around Katsuki's trembling form and hold him close. He's lifted off the ground, and tucked into Izuku's secure embrace. Katsuki's legs feel like jelly as he lifts them to wrap around Izuku's waist, and Izuku supports him with warm hands against the back of his thighs.
Once he's safely found purchase, Izuku gets back to business.
"Ochako," he orders above Katsuki's head, words sharp and venomous. "Get them all home safely and make sure Kirishima doesn't do anything he'll regret."
Ochako is another alpha— one of Izuku's best bodyguards. If Izuku isn't gonna handle it personally, Ochako is the next best choice.
"Got it, boss."
Katsuki doesn't pick his head up as she does as was ordered of her, instead letting his nose press directly to Izuku's neck. Izuku's ire is dripping off of him like a poisonous haze; still, just being near him makes that scared feeling unfurl from around Katsuki's lungs and helps him breathe easier.
"I wanna go home," Katsuki sniffs.
Izuku, of course, turns all his attention to Katsuki then. His scent bursts out, comforting and gentle and perfect. It makes Katsuki go boneless, content.
"I've got you, Kacchan. Just rest and we'll be home soon."
And, in the safety of his alpha's arms, Katsuki has nothing else to worry about.
---
Katsuki doesn’t let go of Izuku until long after they're home. At Izuku's estate instead of his own.
Izuku sends most of the alpha Yakuza away, and the remaining ones are sent further down the halls to give them privacy. Katsuki clings to his front the entire while.
He's only a little embarrassed to be acting like such a baby now that it's just the two of them versus the whole group, but even the thought of letting go of Izuku until they're both in the safety of his nest has a keening whine building up in the back of his throat.
Izuku calms him with a quick nuzzle to the top of his head and another murmured, "I've got you, Kacchan."
"I know," Katsuki mumbles. "Alpha…"
Izuku inhales deep, his chest rising with the motion.
He doesn't respond for a moment, instead letting Katsuki down against the soft mattress and gathering the bedsheets around them.
It makes Katsuki shudder as he realizes that Izuku is hurriedly forming a nest around him. Just for Katsuki.
Katsuki's head swims a bit, his thighs squeezing together to stop from offering himself up immediately to Izuku's gaze. If only because he can't stop fucking crying like a baby the more Deku hums and coos at him.
"You're okay," Izuku whispers. "I got to you in time."
"I k-know," Katsuki huffs. "Shouldn't have happened anyway."
"It shouldn't have," Izuku agrees.
His eyes are downturned, and Katsuki can tell specifically by the way his eyebrows are drawn together that he's upset. That he's pissed, actually, and trying to hold it in.
Izuku's hand, large and warm and gentle, is settled right above Katsuki's chest as he gets lost in thought. Katsuki squirms as he thinks about how much better it'd feel against bare skin.
"Alpha," Katsuki breathes, nothing more than a whisper.
Still, it makes Izuku move again. He slowly unbuttons the white shirt Katsuki had beneath his already undone blazer.
"I'm just gonna help you change," Izuku says, half to himself. "And then fix your heat."
"Deku," Katsuki whines, though he's not sure exactly what for.
Izuku does, though, and drops their faces together to kiss him quiet. It isn't the first time they've kissed, but it's the first time it's felt like this.
His lips brush their way against his jaw, prompting Katsuki to bare his neck directly to the alpha’s gaze. Freely showing his submission to the only alpha Katsuki would ever want.
Izuku gulps, audible in the quiet beyond Katsuki's heavy breathing as his heat begins to ravage its way through his lower belly. He wanted Izuku to touch him more, but he was stalling above Katsuki's belt.
"I need to help with your heat, Kacchan," Izuku mumbles. "But… I shouldn't. I shouldn't. But I don't know if medicine will help at this point."
"I don't want medicine. I want you."
Izuku whispers a hoarse, "Fuck," under his breath, dropping his head so that it rests in the curve of Katsuki's neck. Katsuki can feel him press his teeth directly against the swelling scent gland, eager to sink into it and mark him permanently.
Katsuki stays limp and pliant, happy to let the alpha do just that.
Instead, he gets a gentle kiss atop it. When Izuku pulls back, he's licking his lips to directly taste the flavor of Katsuki's scent directly from the source.
Katsuki doesn't have to reach down between them to know that he's hard. He's not sure if it's the heat making him more sensitive to it, but he can just feel the desire radiating off of Izuku in waves.
"I want you, alpha," Katsuki stresses. "Take me already."
"I… shouldn't," Izuku tries again, rushed. As if he's trying to convince himself. "You're so young, and… You just went through something so scary."
Izuku's fist clenches, and he hides his face against Katsuki's neck. When his arms fit beneath Katsuki's back, he's lifted partially out of the nest so that Izuku can hold him that much closer.
"Fuck, I'm so angry. I want to just… hold you tight and be gentle like you deserve— but I can't stop thinking about wringing that alpha's neck for touching you."
Katsuki's breath hitches a bit at the reminder, but Izuku is still with him. He doesn't let himself get scared all over again as he remembers the fear of having Kirishima's teeth near his glands.
Still, he brings a hesitant hand up to his neck anyway, to cover it. Izuku nuzzles at that hand, as if to comfort more.
"He was a dummy for letting himself get taken over by his instincts," Katsuki starts. But the harsh words are undercut by the way his bottom lip trembles.
Soon, heavy tears drip off his lashes all over again, and Izuku gently shushes him as he gathers him up tighter.
"I’m sorry— I'm sorry, baby. I shouldn't have brought it up. Just— let me take care of you, Kacchan. There's no need to think about anything else except you and me right now. Okay?"
Izuku tilts Katsuki back against the soft of his nest, settling his hips between Katsuki's thighs. Then he kisses him, just a sweet brush of his lips across Katsuki's trembling ones.
"It's okay to cry," Izuku says, gentle in the way that he runs his hand down Katsuki's chest. He mulls over his next words for a moment, before he kisses Katsuki again and adds, "But I'm going to make you feel better now."
"How?" Katsuki sniffles wetly. He's rough in the way that he swipes away his tears, angry that they even spilled over, and Izuku laughs quietly as he presses his palms against the curve of Katsuki's jaw.
"I'm going to take care of your heat. It hurts here, right?" Izuku nudges their bodies together, and Katsuki lets out a breathless noise when it makes Izuku's thigh rub just right against his clit, still hidden beneath two layers of clothing.
"Can I help you feel good, my omega?"
The words heat through his veins, just like the gentle touch that warms his skin as Izuku finally slips his fingers beneath his belt.
"Make my heat go away," Katsuki orders. And then, almost hesitantly, he adds, "… Please, alpha."
"Of course, baby."
With that, Izuku hurries to finish undressing the omega writhing in his hold.
He slides Katsuki's pants down quickly, though he doesn't bother taking them entirely past the knee. Instead, he seems to get distracted with the way Katsuki's small cock softly twitches against his belly. It's already smearing arousal there.
He tips his thumb against the mess, painting it further across Katsuki's skin.
Katsuki finds himself breathless, being exposed so soon to his chosen alpha. Just beneath his cock, his hole twitches with the need to be filled up by those same fingers that seem to catalogue every inch of his skin.
Unfortunately, they don't sink inside him immediately and bring him to his first orgasm. Instead, they pause at his waist.
When Katsuki blinks his eyes open, as they had closed as soon as Izuku reached for his cock, he finds Izuku staring down at his body. Not with desire, though, but with heated anger still simmering beneath the surface.
Beyond that, though, Izuku's face is carefully blank as he passes over the red marks on Katsuki's hips, where Kirishima had gripped him too tightly. But the skin isn't broken, and it isn't likely to stay bruised. It just pinches a little when Izuku passes his touch over it.
"Does it look bad?" Katsuki asks anyway.
"Never."
Izuku drops flat against the bed to pepper the area in kisses. It replaces that moderate feeling of pain with a tickle instead, and makes Katsuki hide his blushing face with the backs of his palms.
This also helps muffle the wanton sound that spills past his lips when Izuku continues his line of kisses closer and closer to between Katsuki's legs. He isn't sure when he's ever been wetter than now, but he can feel more building as Izuku lays a careful kiss directly against where Katsuki's slit meets the shaft of his cock.
Shaky gasps are pulled out of him as Izuku continues doing it, until his lips shine with the slick that has spread that way.
When he licks his lips, his eyes roll and he lets out a quiet moan, as if it's the tastiest thing he's had in a while.
Katsuki isn't expecting him to immediately dive back down, especially not with tongue this time.
"D-Deku!" Katsuki moans, reaching down between his legs. His fingers tangle in Izuku's hair, but they end up fisting against his scalp when Izuku licks from the bottom of his slit to the top in one swipe, as if to map out the chubby lips and imprint it against his tastebuds.
Katsuki trembles when Izuku glances up at him, and Izuku hums playfully.
"Feel good, Kacchan?"
"My tummy hurts," Katsuki complains, wobbly. He just wants Izuku's mouth back on him.
Izuku smiles at him, brushing his thumbs across Katsuki's flushed, heated slit. "It's your heat, baby. I'll make it feel all better."
But first, he strays back towards those marks that he has yet to stop touching with his other hand. He rubs in gentle circles the darkest of the spots, before he lays his mouth directly overtop and suckles the tender skin, until more blood flows to it.
Katsuki trembles at the slight pinch, but especially because Izuku's mouth is back on him.
"Sorry, Kacchan," Izuku huffs. "I shouldn't but… I just— need this. Need to mark you as mine."
The thought of Izuku claiming him tonight makes Katsuki go even more wild with need. Izuku leaves two hickeys in that one area before he moves on to the other hip, opening his mouth wider so that the sharp divots of his teeth just barely prod against the skin. To make darker the marks put on him by someone who shouldn't have touched him in the first place.
"You're mine," Izuku growls. The words are fierce, just as feral as Izuku had felt when he saved Katsuki.
Katsuki grunts in agreement, his head falling back against the pillows that Izuku had stuffed behind him to make up the bulk of the nest.
"Yours," he sighs, happily.
Izuku brushes his fingers along Katsuki's aching slit, and almost all thought leaves him then. He spreads his legs wide to make room, to entice Izuku in, but gets hampered by the pants still caught around his legs.
Izuku slides them fully down one side, but doesn't bother with the rest, too eager to help his omega's first heat pass smoothly.
As soon as his weight settles between Katsuki's legs, he feels himself dropping into a calm headspace all over again.
"I'm going to… make love to you, alright?" Izuku blushes at the words, as if Katsuki hasn't been to Sex Ed. before. Still, an endearing feeling buds in his chest as Izuku continues, "It's the best way to make your heat go away and I really…"
Izuku nudges their cheeks together, purposefully transferring their scents back and forth. "Really don't want to let you out of my sight just yet."
Katsuki nods his head. He didn't want Izuku to leave either.
"Scent me more?"
Izuku hums as he drops down to do just that.
His suit is soft against Katsuki's bare chest as he covers Katsuki's body with his own. He finds Katsuki's wrist somewhere in the mess of bedsheets around them, and helps to spread his scent to nest directly at the same time he scents Katsuki's wrists.
Katsuki fists his palm against the sheet, and lets a trembling moan ease through him when he feels Izuku's hand sneak between them and begin to unzip his trousers. The cold of the zipper touches Katsuki's bare thigh and makes him shiver, but Izuku makes up for it by gently thumbing across the spot he touched.
He can feel Izuku hold his breath as his cock spills out, fully hard and throbbing. Just for Katsuki.
Katsuki's own twitches, and Izuku grins as he lets the head of his cock settle against the quivering hole offered up to him.
"You're so beautiful, Kacchan," Izuku admits. "Such a perfect omega for me. I want to make you cum so bad."
A laugh is startled out of Katsuki at the words, if not embarrassed around the fringes. "M-make me, then."
The tremble in his voice makes him duck his head down, but Izuku tilts Katsuki's face back up with a quick touch to his chin.
"Let me see you," Izuku urges. "I want to see it all."
"You're so, ahhh," Katsuki is interrupted as a gasp steals its way out of his lungs. Izuku presses more insistently at his hole, until just the very tip slips past. And it slides in easily, the hole fluttering to try to urge the alpha atop in him inside further. Katsuki's heat is making him dizzy as he just barely holds himself back for begging for it all.
Izuku stops, though, to let the full rush of pleasure wash over him. Katsuki is speechless for a moment, just from the tip, and finds himself tangling his fingers against the soft hairs at the nape of Izuku's neck.
When he recovers, Izuku is smiling at him again. All giddy happiness.
"Embarrassing," Katsuki finishes, mouth dropped open in a pant. "Hnngh, fuck…"
"Is it too much, baby?"
"Need more," Katsuki whines.
And it was true. Just that taste, just having those few inches of alpha cock parting him for the first time ever… Katsuki is surprised he hasn't shoved Izuku over to ride them both to completion immediately.
It helps that Izuku is surrounding him at the moment. His scent is wrapped around him securely, mixing with Katsuki's own. He can feel his chest beginning to rumble with the onset of a content purr.
Izuku plants his palm against the mattress for leverage, just beside Katsuki's head, and slowly feeds him more of his cock.
"Hnngh— yesss…!" Katsuki gasps, interrupting his moan.
The scent from Izuku's wrist gland is so close that Katsuki can't help but nuzzle against it as he gets filled. It's satisfying down to his very last cell, until Katsuki's toes are curling as Izuku's cock slides directly across what must be his g-spot.
Katsuki had never explored it like this before, and it feels so much better to have something hot and firm and— and from Deku pressed up against it.
He can't help the overwhelmed, happy tears that build up at his waterline again.
Izuku pauses, but Katsuki urges him to keep going with a quick squeeze from his thighs against his hips.
"I don't wanna hurt you, baby. Don't let me go too fast."
"It feels good," Katsuki begs. "Go faster. Claim me."
Izuku breathes out a shuddery moan at the command, his mouth parting to show the glint of his fangs in the rising moonlight. His cock sinks in deeper, displacing an embarrassing amount of slick. It drips down and coats Katsuki's ass, only to soak into the nest.
Izuku must feel it, too, because he circles his fingers against the soft fat of Katsuki's thigh and lifts, to spread him out wider.
Then he slides his cock in all the way.
Katsuki gasps, his chest heaving at how intensely full he feels.
"You're so perfect, Kacchan."
Katsuki flusters at the praise, but Izuku continues. "My perfect omega. Look how pretty you are for me, taking my cock just like that."
Is he pretty like this? Spread out, fucked open, almost fully clothed compared to Izuku still donning his suit?
Somehow, the sudden acknowledgement of their different states of dress sends another wave of abashed arousal through him.
When Izuku slowly slides his length out, only to immediately rut every inch back in, Katsuki can't be bothered to think of anything else but Izuku in the moment.
His body is tugged and pushed up and down the bed, only kept still by Izuku's hands on him. It feels so good to be maneuvered by such a strong alpha like this, Katsuki practically preens each time Izuku adjusts his hips to keep fucking him just right.
Izuku squeezes his palm down, where it has drifted towards the outer area of Katsuki's thigh, and Katsuki hisses when that makes his bruises ache.
Izuku pauses just briefly, before he continues that maddening, steady pace that is shoving Katsuki up up up towards what must be his first orgasm. It's intense, overwhelming, it's— it's perfect.
"Mine," Izuku grinds out. His hand trembles as he squeezes again, and moans when Katsuki shudders at the feel. "These are my marks, omega."
Katsuki trembles, hardly able to think of a response other than another wanton moan.
"M-more, alpha… Need it so bad."
Izuku drops down all at once, his warmth overwhelming as he lays chest to chest with the writhing omega squished beneath him.
When they kiss this time, it's passionate. Not like the little chaste kisses Izuku used to give him when Katsuki would pout and huff. Not even like the ones he'd peppered across Katsuki's lips early that evening.
It's their tongues wrapping together, writhing together, until all Katsuki can taste is Izuku. It's as if this alpha is taking hold of every one of his senses and claiming it for himself. Katsuki wants nothing more than that.
When the kiss breaks, Katsuki shyly hides his expression against the underside of Izuku's jaw. He can't hide the gasping moans, though, with how close they are.
"Perfect," Izuku praises, tilting forward to murmur the word directly against Katsuki's ear.
And when he opens his mouth again, it's so that his teeth can nudge against Katsuki's scent gland directly.
Katsuki's insides tremble around Izuku's length, belying how eager he is to feel them sink into his flesh and mark him all over again. His own mouth opens in response, lips closing around Izuku's own clothed neck.
His button-up is thin enough that he can feel Katsuki's drool soak in, and he encourages Katsuki to find the bare skin with a few nudges to his jaw.
"That's my good boy," Izuku pants, fingers shaking when they drop down to where their hips are joined. He eases himself in and out of Katsuki slowly, nothing more than little ins-and-outs that leave Katsuki stuffed.
He's just found Izuku's jugular when his alpha presses his thumb to Katsuki's clit. He prods at it, gentle nudges until Katsuki is trembling in his hold for an entirely new reason.
His teeth find Izuku's scent gland. The taste explodes across his tongue.
Katsuki bites down first, as his orgasm finds him.
"Fuuuck," Izuku swears above him, his head angling back as he moans hoarsely at the ceiling. When he lifts himself, Katsuki lifts with him. Then he's being supported by a hand against his lower back so that Izuku can fuck up into him, letting gravity help most of the way.
His pussy spasms, to milk the alpha below him dry. To encourage him to knot and lock them together in another way.
When Katsuki pulls back, his mind buzzing in excitement, Izuku's teeth dig into his shoulder. And then he's being claimed, the pinch of pain overshadowed immediately by the pure euphoria of feeling his entire being shift to align with Izuku's.
It's as if the moon and sun met for the first time. As if fire and water combined in a dance. Katsuki practically blacks out as he feels everything and nothing all at once, hyperfocused only on his scent grabbing hold of a bit of Izuku's and stealing it to meld together. Permanently.
When Katsuki comes to again, it's to the feeling of Izuku spilling his cum inside of him. As if the claim wasn't enough, his instincts are completely satiated from that warmth flowing in the deepest part of him. It overshadows what little discomfort is left from his heat, and leaves him limp, boneless, and entirely soft.
Katsuki mumbles nonsense beneath his breath as Izuku cuddles him close, careful not to dislodge himself in the aftermath. Katsuki's legs loosely wrap around Izuku's hips to keep him there, too.
He doesn't notice the alpha shifting them higher up the bed, away from the wet spot they created, until he's flipped and cuddling up against Izuku's chest from above this time.
His arms lay limp, splayed out in either direction as Izuku gently pets him up and down his back. His uniform is tucked down his arms until he's fully bare, and tossed off to the side to be sent to the cleaners. His pants, he must've lost somewhere in the middle of it all, because all that's left on him are his socks.
He doesn't realize he's letting out soft, mewling sounds until Izuku starts to chuckle at him.
"Feel good, baby? Is your heat going away?"
"Mmm," Katsuki eloquently responds.
Izuku's chest rises and falls with his deep, fond sigh, and subsequently so does Katsuki. He cuddles impossibly closer, until Izuku reaches to tuck some sheets around them so that he doesn't catch a chill.
By the time he comes back to himself, Izuku has softened and slipped out of him. Katsuki belatedly realizes that he knotted outside of him, especially when he feels the cum stuffed deep inside begin to trickle back out.
"Your suit's gonna get stained," Katsuki huffs, reaching between them to prod at his swollen hole. "Asshole."
Izuku lets out a startled laugh.
"'Asshole'? What happened to that sweet omega I was just cuddling?"
"You fucked him out of me," Katsuki tuts.
At that, Izuku quiets. He squeezes his arms tight around Katsuki's back, only to immediately let go when that tugs on a bruise Katsuki hadn't even realized he'd gotten.
As soon as Izuku feels along the swollen skin, the gentle ambiance around them grows heated with his growing anger again.
"Deku…" Katsuki starts, but Izuku interrupts him. Which means he's upset, because Izuku rarely interrupts him when they're being serious.
"Shoulda killed him," Izuku whispers, though the words are sharp. "I wanted to rip his jaw off when I saw him."
His hands clench into tight fists behind Katsuki's head, and Katsuki reaches up to place his palms against Izuku's biceps, to lower them down.
"I'm glad you didn't. He's still my friend."
Izuku grumbles something beneath his breath, but Katsuki catches something along the lines of, 'my omega,' beneath the mutterings.
He butts his head against the underside of Izuku's chin.
"Kirishima doesn't actually want me like that. Idiot has probably never been so close to an omega in heat before. Outside of all of this, he's only ever had eyes for Raccoon Eyes, anyway— he just lost control."
Katsuki shudders all at once, as the memory of teeth against his scent gland come back unbidden. It'll probably be a while until he and Kirishima can be alone in the same room, but he still considers him one of his closest friends.
"He's… he's probably beating himself about it anyway. Didn't need you to do it for him."
"Wish I did," Izuku sighs. "I'm so crazy for you, Kacchan… I don't know how I held back. It was so scary how close things got to… to being so bad, you know?"
Katsuki nods. Of course he knows. He'd been close to breaking down at the thought of being eternally bound to someone other than the alpha he was cuddled up against.
Despite that, he's grateful that Izuku didn't let it keep escalating.
"Still… Thanks for not hurting Shitty Hair. It was—" Katsuki doesn't want to agree that it was scary because he hates being scared, but…
He finishes with a scoff. "I'm glad you made it to me."
"Always. I'll always come get you." Izuku grabs him and pulls him close, hiding his expression against Katsuki's neck all over again. "But I hate it so much, Kacchan. You're mine."
Katsuki preens at the declaration. It was rare when Izuku let his more negative emotions get the better of him, but Katsuki will gladly welcome his alpha being greedy over him.
Especially when it comes to him getting jealous about another alpha. Katsuki knows the feeling well— especially with Deku and that shitty omega, Todoroki Shouto, getting closer than ever now that their clans are starting to join forces.
"I shouldn't have claimed you, though," Izuku bemoans miserably. "I'm so sorry, Kacchan. What will our parents think…? You're so young. I should've waited like I planned."
Katsuki perks up, eyes blinking eagerly. "Like you planned?"
Izuku's face goes red. "I… yes— I…"
Izuku scrambles for his words, and Katsuki snorts at him.
"I've known forever that I wanted you as my alpha. It just makes sense that it happened at my first heat."
He pauses briefly.
"…Unless you regret it."
He doesn't realize he's frowning until Izuku is gathering his face up in the palms of his hand and kissing a smile back onto his face.
"Of course not Kacchan. Out of everything in our life, I would never regret mating you. Not ever."
He says it so resolutely that Katsuki can't help but believe the words. He nuzzles his alpha (his alpha!) and leans in closer to bask in his scent.
Katsuki presses their foreheads together, and can practically hear Izuku's brain running a mile a minute in nervous panic.
"Our parents though—"
Katsuki interrupts him with a look. "My old hag and your ma have been wanting this to happen for as long as I remember. Why else would they let me hang around you?"
"To protect you?"
"We literally hire people for that."
"To teach you about the Yakuza, then."
Katsuki clicks his tongue. "She teaches me that herself. Dad, too."
"Then—"
"Deku. Just face it. You're not getting rid of me from now until the end of ever."
Katsuki circles his arms stubbornly around Izuku's shoulders and hugs him as tight as he can. "So you better just get used to the idea of being my alpha for the rest of your life, 'cause I'm not letting you go."
Izuku's heart picks up beneath his chest, and Katsuki knows his own is doing the same. He's not usually the one for sappy words like that, but he meant it.
A gentle touch pats against the back of his head as Izuku easily hums his agreement.
"Of course, Kacchan. For the rest of our lives."
And there's nothing anyone else can say to change that fact.