nsfw / #dkbk

cw: age gap

“We have a problem,” is the first thing Kirishima says to him.

Izuku resists the urge to rub his temples and sigh. Of course there’s a problem. Whenever he comes into the agency, there’s *always* a problem.

“What is it?” Izuku asks, wondering when the thrill of hero work turned into headache after headache. Is this how Aizawa felt all those years?

“Uh, it’s better if you see for yourself,” Kirishima says, which doesn’t bode well.

Izuku follows him down the hall, nodding to a few starstruck sidekicks as he passes.

They stop at a room that’s caught between an office and a break room. Mostly it’s used for private conversations, or when one of them needs to steal some sleep between patrol shifts.

When Izuku first walks in nothing seems out of the ordinary. Sero is standing in a corner of the room, arms folded over his chest. Kaminari is nursing what’s probably his fifth cup of coffee today and–

“DEKU?!”

There, seated on the couch adjacent to the door, is Kacchan.

And he’s… tiny.

He can’t be older than fifteen.

Katsuki’s jaw is slack with shock as he takes in Izuku from head to toe. His height (he’d shot up sometime in their third year of UA), his scars, his “heroically” (according to all the gossip rags) chiseled jawline.

Katsuki’s eyes finally land squarely on Izuku’s thick thighs and stay glued there for longer than is polite. Izuku clears his throat.

“Kacchan,” he says, shifting his weight uncomfortably while Sero stifles a laugh into his fist, pretending it’s a cough.

Katsuki’s gaze snaps up to his face and his eyes narrow in a glare. It’s significantly less intimidating now that the top of Kacchan’s head barely reaches his shoulder.

“You can’t be Deku!” he says, voice laced with suspicion.

“Deku isn’t that...” Kacchan turns pink and his lips start to shape a word that looks suspiciously like ‘hot’ before he catches himself, “...big.”

His voice cracks as he says it, and Katsuki glares at Izuku like it’s his fault. Kirishima snorts.

Izuku lets the comment slide for the sake of his sanity and refocuses on his colleagues.

“So,” he says, glancing between the three of them, “how did this happen?”

“Quirk incident,” Kirishima says, which is code for ‘fuck if I know’.

“We have some leads, but we figured he’d want to stay with a familiar face.”

Izuku bites his lower lip and glances at Katsuki, who is still sitting sullenly on the couch and pointedly not looking at him. “I don’t know if that’s a good idea...”

But Kacchan’s parents are away in Paris for Fashion Week right now, and he can’t just leave Katsuki alone like this. There’s no telling what could happen if villains caught wind that Ground Zero is little more than a helpless kid right now. Still, Katsuki hated him at this age.

“It’s fine, Deku,” Katsuki says, getting to his feet and shoving his hands in his pockets. He must have borrowed some clothes; they’re too big on him.

“Let’s go. I don’t want to hang around these extras,” he scoffs.

Sero vibrates silently with laughter, and Kaminari raises an eyebrow.

“So he really was always like that,” he says, taking another sip of coffee.

Katsuki immediately whirls on him, bristling.

“What the hell is that supposed to mean, dipshit?” Kacchan says, palms smoking.

He looks about five seconds from launching himself at Kaminari. Izuku grabs him by the collar of his shirt before he can.

“Alright, Kacchan, let’s go.”

He practically drags Katsuki out of the room while Kaminari cheekily waves goodbye to them.

“Get off of me!” he snaps, shrugging off Izuku’s touch like it burns. He’s blushing again, staring down at his shoes with a scowl. Izuku sighs, deciding to just be grateful Katsuki’s cooperating at all.

It’s honestly the quickest walk out of the agency Izuku’s ever experienced.

Any time a starry-eyed sidekick or blushing intern tries to approach him, Kacchan gives them the same glare he used to give Izuku in middle school.

He‘d be lying if he said it wasn’t funny watching some of his fellow heroes get intimidated by a surly teenager.

“Nice car,” Katsuki scoffs when they exit the building and walk out to the curb. He says it like an insult, but Izuku can tell he’s impressed by the way his eyes trace over the shiny black paint job.

Kacchan slides into the passenger seat, clearly trying not to look wowed by the fine leather interior. The car always manages to smell brand new even though Izuku has been driving it for roughly a year now. As he buckles his seatbelt, Katsuki shoots Izuku a furtive glance.

“I hope you can drive,” he snarks, crossing his arms over his chest like Izuku is taking him to a funeral instead of his penthouse in Musutafu.

Izuku turns on the engine, replying in an even voice, “That’s why I have a license, Kacchan.”

Izuku shouldn’t feel as satisfied as he does watching pink spread across Katsuki’s face from the corner of his eye. He’s a hero for God’s sake. Gaining satisfaction from ribbing his rival when he’s not even out of puberty yet is just low.

Draping his arm around the back of Katsuki’s seat, he glances over his shoulder as he pulls out onto the road. When he refocuses his gaze forward again, scarred hand moving down to grip the gear shift, he notices Katsuki’s stare.

The blond’s pupils are blown wide, and Izuku follows his gaze down to his own hand wrapped around the gear shift.

Kacchan immediately looks away but Izuku is left bewildered. Only a honk from the driver behind him reminds him to put the car in drive.

He keeps both hands on the wheel as he hits the gas, praying his face isn’t as red as it feels.

Kacchan is so… so… *gay*. How had Izuku never noticed before? He feels like banging his head against the steering wheel for being oblivious this whole time.

He’d been so sure Katsuki was straight, but now… Well, maybe when Kacchan was back to normal Izuku would ask him if he wanted to grab coffee or someth—

“What are you thinking about?”

Katsuki’s voice, higher pitched than he’s used to, breaks him from his thoughts.

Izuku feels his face flush as he fumbles for an answer besides “asking your future self out on a date” and comes up empty.

“N-nothing, Kacchan!” he says instead.

Katsuki scoffs but when Izuku glances over at him he has a smirk on his face like the cat that ate the canary.

“Once a Deku, always a Deku,” he says in a satisfied voice.

Izuku just sighs.

Katsuki has to admit, albeit begrudgingly, that Deku’s penthouse is pretty fuckin’ impressive. It has floor to ceiling windows looking out over the city, and polished hardwood floors occasionally embellished with a luxurious carpet.

It’d be like something out of a magazine if everything wasn’t covered in All Might paraphernalia—a folded All Might throw resting on the leather couch, glass cabinets filled with limited edition figurines, posters tastefully framed and hanging from the walls.

It’s more adult, but Deku is still Deku after all, even if he doesn’t look like it.

Katsuki tries his best to feign nonchalance, but he can’t help stare at some of the newer (at least new to him) pieces of merchandise.

When he finally tears his eyes away, he catches Deku watching him with a half-smile.

Katsuki scowls back even as he feels heat creep up his neck, settling in the apples of his cheeks and the tips of his ears. Stupid fuckin’ Deku. How dare he grow up so *hot*.

“Make yourself at home, Kacchan! The guest room is upstairs,” Deku says, gesturing to a winding staircase in a corner of the room. He gestures to another door a little ways away. “And that’s the bathroom.”

“Whatever,” Katsuki says, trying to pretend like it’s not weird that Deku

is apparently swimming in wealth. He must be a pretty popular hero. Maybe even in the top ten. Definitely lower ranked than Katsuki though, of course.

“We should probably get you some clothes,” Deku mumbles, worrying his lower lip between his teeth.

He has a scar on the left side of his chin—nothing like the big, painful looking swathes of skin on his arms, just a tiny little nick. Katsuki wants to lick it. “And some toiletries. Maybe a cellphone. After all, we have no idea how long you’ll be stuck like this...”

“Quit your damn muttering, nerd,” Katsuki huffs, flopping down on the couch. He grabs the remote off the glass coffee table in front of it, the surface peppered with magazines and mail (the damned nerd really needs to tidy up), and turns on the TV.

Immediately his retinas are assaulted by Deku’s wide, blinding smile on screen. The camera slowly zooms out to show the rest of him. He’s in his hero costume holding a tube of toothpaste and standing in front of a minty blue backdrop in the most cheesy way possible.

“... the number one toothpaste brand to keep our number one hero’s smile healthy, strong, and bright!”

Katsuki drops the remote. It clatters to the floor, startling Deku who walks over and picks it up, turning off the tv.

“Kacchan,” he says carefully.

Ugliness starts to well up inside of him—shock, envy, rage, but also a weird sort of knowing, like Deku being number one was something he’d accepted a long time ago.

“You’re the number one hero,” he says, heart pounding in his ears so loud he barely hears the crackle of

tiny explosions tickling his palms. “Not me, but *you*?”

Deku’s mouth ticks down into an uncharacteristic frown. He looks disappointed, and Katsuki can’t take it. As if Deku has any reason to be disappointed! He got everything he ever wanted, so what did that leave for Katsuki?

Tears burn hot behind his eyes, and Katsuki gets up and runs upstairs before Deku can see them fall.

“Kacchan, wait!” Deku yells after him.

He throws open the first door he sees and slams it shut behind him, breathing hard as he turns the lock.

He waits with his back pressed to the door, heartbeat loud in his ears, but no footsteps follow.

Katsuki turns his attention to the room, wiping the tears from his eyes with a sniffle. He’s definitely not in the guest room.

There’s a king sized bed with an assortment of accent pillows in shades of blue, navy and beige, topped by a thick comforter. On the right there’s a door which probably leads to the master bathroom, and more ceiling to floor windows on the left. Pushed against the wall facing

the bed is a wooden dresser, and above that an expensive looking flat screen.

Katsuki doesn’t bother flipping on the lights, just crawls into the bed, pulling the comforter up to his chin. It smells like Deku, and Katsuki hates that he finds it weirdly comforting. Ugh.

Honestly, Katsuki can’t remember much about the last few weeks of his life. He knows he got into UA, that Deku somehow managed to manifest a quirk, but his memory is fuzzy at best. And even if Deku had managed to get into UA too, he was still *Deku*.

How the hell did *he* end up the number one hero instead of Katsuki?

Sure, he looks way stronger now. Not grotesquely muscular, but nothing to scoff at either. Katsuki knows that for a fact; his stupid green bunny suit practically clings to him like a second skin and, well—

there’s nothing little about Deku anymore. Still, it just doesn’t make sense. Katsuki is the best.

He’ll just have to show Deku who’s really on top.

Katsuki shifts on the bed, breathing a little heavier at the thought of it.

He can’t help but think about beating this new hero version of Deku, smirking down at him in victory while he’s splayed out beneath Katsuki’s explosive hands. Deku staring up at him with those green eyes framed by dark lashes. The freckles on his cheeks.

The stupid little scar on his chin.

Katsuki groans, sliding a hand under the covers to palm himself through the sweatpants they’d given him at the agency. Fuck Deku for growing up so gorgeous. It’s not Katsuki’s fault he’s hard over the idiot.

He remembers the car ride, how broad Deku’s palm looked wrapped around the gear shift. The nerd’s got a man’s hands now, big and scarred with rough palms and crooked fingers. Katsuki wonders what they’d feel like, turns his face into the sheets to pant as he rubs a hand over

the outline of his cock. He’s never touched himself without something in between for obvious reasons, but Deku could. Deku could probably do a lot more than touch him too.

Katsuki’s sure he’s strong now, a lot stronger than he himself is, not that he’ll ever admit that out loud.

Deku could probably turn the tide of their fight easily, flip their positions and pin Katsuki down, grind that amazing fuckin’ ass against his dick.

“Deku,” he sighs, thrusting his hips against his hand. Katsuki hates him; he shouldn’t want him, but he does.

He thinks about Izuku’s hand again, the one with the crooked fingers, imagines it sliding up his chest and wrapping around his throat, and cums into his pants with a groan.

Katsuki practically melts into the sheets in the afterglow, eyelids growing heavy.

Sleep closes in on him and in the dark, surrounded by Izuku’s calming scent, he can’t fight it.

Katsuki wakes up with regrets. Namely that the inside of his pants are crusted with dried cum. At least he’s alone. He doesn’t know what he would’ve done if Izuku had come to wake him up. He kicks the blankets off him and climbs out of bed, trying to make as little noise as

possible, paranoid Deku might burst in at any moment.

He takes a shower first. The master bathroom is a little cramped, but no less fancy. Disgustingly enough, Deku only has a 2 in 1 shampoo and a bar of soap; they’ll definitely need to go shopping soon.

Once he’s clean, he’s faced with another problem: clothes. Towel wrapped around his waist, Katsuki walks back into the bedroom and opens the dresser, rifling through each drawer.

Deku owns a pathetic amount of clothing.

Grumbling at his lack of options, Katsuki pulls on an All Might sweatshirt—it looks too small for the nerd, but he probably couldn’t bear to throw it out—and a pair of shorts since the pants, much to Katsuki’s annoyance, are too long and would make him trip over his own feet.

The clothes practically hang off him, and Katsuki has to push the sleeves of the hoodie up to his elbows to keep from being swallowed by the fabric. Balling up the clothes he’d worn last night, he puts his dirty clothes at the very bottom of the hamper in the corner of the room.

He’ll have to sneak back and put them in the wash once he figures out where Deku does his laundry.

Shoving his hands in his pockets, half out of habit and half to keep his shorts from slipping too far down his hips, he makes his way downstairs.

Katsuki can hear the sizzle of something cooking as he turns the corner and pauses just outside the kitchen, soaking in the sight of Deku standing in front of the stove in nothing but a pair of grey sweats. He’s got even more scars on his torso than his arms, but it does nothing

to distract from the fact that Deku is built like a brick shithouse. Katsuki swallows hard as he ogles the two dimples framing Deku’s lower spine.

“Kacchan, good morning!” Izuku says, turning to him with a sunny smile and abs that look photoshopped.

“What happened to your clothes?”

Katsuki’s fantasy from last night comes rushing back and he blushes, snapping, “Shut the fuck up, Deku! Like hell I was gonna wear the same shit two days in a row!”

Deku doesn’t even flinch, just raises an eyebrow and shrugs.

Katsuki tries not to watch the way his back muscles shift with the motion.

“Breakfast will be ready in a minute,” he says, holding an egg above the pan on the stove and crushing it. Yolk and shell drip down and sizzle.

“What are you making?” Katsuki demands, walking over and peering into the pan. He’s standing so close to Deku that his palms start to get clammy.

“Um,” Izuku says with a sheepish grin, “an omelette?”

Katsuki shakes his head in disgust and shoulders his way in front of the stove. Well, he *tries* to shoulder his way in front of the stove but, to his embarrassment, Deku doesn’t even budge. Eventually the idiot takes a hint and steps back on his own,

still hovering far too close for comfort.

Katsuki ‘tsks’ as he grabs the pan and holds it over the trash, using a pair of chopsticks to empty the mess Deku made into it.

“You’re hopeless at any age, Deku,” he scoffs. “Go make yourself useful and set the table!”

Izuku grabs plates from the cabinets above the counter while Katsuki watches from the corner of his eye. He can’t help but trace every scar on Deku’s torso with his gaze, wondering what they’d feel like under his hands.

Five minutes later, Katsuki slides a perfect omelette onto

Deku’s plate.

“Wow, this smalls amazing, Kacchan!” Izuku praises.

Katsuki’s ears turn red and he scoffs, turning back to the stove. “Of course it does! Only dekus like you couldn’t make something this easy.”

Izuku ignores the insult, already digging in. “You don’t want half?”

Katsuki eyes the greedy way Izuku is eating his omelette, like he hasn’t had a home cooked meal in months, maybe years. “I’ll make another one for myself.”

Izuku makes a noise of acknowledgment around his mouthful of food.

By the time Katsuki is finished making his own breakfast, Deku is already putting his dishes in the sink and washing up. Katsuki watches the shift of his back muscles while he picks at his omelette, doing more ogling than eating.

“Kacchan, we should go shopping for you today.”

Katsuki thinks about the only pair of pants he owns, now dirty and crumpled at the bottom of Izuku’s hamper.

“Whatever.”

It’s the first day Izuku has taken off in months. Since becoming number one. he’s been focused on saving as many lives as possible, living up to the Symbol of Peace title he’d inherited, which means long, unpredictable hours with little to no spare time.

But he can make time for Kacchan, especially after the way he’d reacted to the reality of Izuku’s hero ranking. It seems silly now; ranking is trivial in a profession as dangerous and demanding as theirs is.

Kacchan certainly doesn’t care anymore, but to a fifteen year old Katsuki it must seem like the end of the world. It’s almost cute how hard he took it, crying himself to sleep in Izuku’s bed. As kids, Katsuki had always seemed almost larger than life, an image of victory.

Now, he can’t even fill out Izuku’s shirt, shoving the sleeves up to his elbows so they don’t flop over his hands. Izuku wishes he didn’t find it so endearing. He can’t afford to get too attached to this version of Kacchan,

can’t let himself entertain what future mornings might be like with someone else around. Once Katsuki turns back, there’s no guarantee he’ll want anything to do with Izuku.

Despite that, he still catches himself glancing over at the blond as they walk into the mall.