Archive of Our Own ^beta

In one world, a long life filled with war and violence comes to a quiet, peaceful end. It’s not a life lived without regrets, but he’d long ago made peace with them. 

In another, two lives take their first breaths minutes apart. The first announces his arrival at the top of his lungs. The second regards the world with a sleepy calm. 

“Huh,” Mitsuki says, staring down at the newborns in her arms. The screeching one’s hair is the same shade of blond as her own, while the other’s is a pale silver instead. Not a color that runs in either of their families, but stranger things have happened. “Guess they’ll be easy to tell apart, at least.” 

“You can tell which one takes after you,” Masaru jokes as he rubs his ear, wincing. 

“Oh, shut it,” Mitsuki snaps. She’d smack him if she had a free hand. 

-- 

One thing Mitsuki realizes early on as she learns how to be a mother: just because they’re twins, doesn’t mean they’ll be anything alike. 

Katsuki is all brashness and temper. He really does take after her right from the start, and his young age multiplies it by a hundred. He’s loud, impulsive, and extremely competitive the moment he has the smallest bit of mobility. He wants to be the best at everything, and tackles every challenge with everything he has. When he has an opinion, everyone gets to hear it. Sometimes at earsplitting volumes. 

Kashiya, in contrast, is laid-back and easygoing. He rarely argues and lets Katsuki drag him around without complaint, seeming content to go along with anything with a mild air of resignation. He keeps his thoughts and feelings close to his chest. Even as a baby, he’d rarely cried, to the point where she’d started to get worried about it. 

But he still has a thread of unbending stubbornness about the weirdest things. The moment he found an old dusty medical mask at the back of a cupboard, he’d insisted on wearing it at all times, refusing to back down when she tried to stop the habit. After months of arguing with him about it and getting increasingly judgmental looks from strangers as it started falling apart from constant use, she’d finally given up and bought him some reusable cloth ones so he’s at least not walking around wearing that ratty, disgusting disposable thing. 

There are some things the twins have in common, though: outside of their hair color, they’re virtually identical, with the same bright red eyes and facial features. They’re both whip-smart. And they’re both very, very good at getting into trouble. 

Katsuki scowls at her, mulishly holding a wad of tissues to the gash at the corner of his mouth. There are scratches all over his arms, legs, face – everywhere his clothing doesn’t cover is banged up. Kashiya sits serenely next to him, unscathed. 

“What the hell were you two thinking?!” Mitsuki shouts, smacking them both upside the head. “Reckless idiots, the both of you! Parkouring through trees that high off the ground? You’re lucky you didn’t break a leg when you fell! Look at you!” 

“It’s not fair!” Katsuki explodes. “He’s so lazy and and he’s still good at everything! I want to be the best! If he can do it I will too!” 

“There, there. Don’t worry, I still think you’re the best,” Kashiya says, tone full of fake innocent earnestness that doesn’t belong on a literal four-year-old. Where did he even learn that from? 

Katsuki screeches and throws himself at Kashiya, who’s on his feet and narrowly dodging out of the way in an instant. His eyes curve in a smile. 

Mitsuki yanks Katsuki into the air by the back of his shirt, having to hold him at arm’s length to avoid getting hit by his flailing limbs. “No more going to the park unsupervised!” she barks. She whirls around and glares at Kashiya. “And you! Stop baiting him!” 

She’s so sick of their bullshit. How is she supposed to survive another fourteen years of this?

-- 

Katsuki is the strongest. The smartest. The top, the best. He was the first to be born, and now he’s the first one to get his quirk. 

“Look, look!” he yells, palms sparking and popping with tiny explosions. 

Kashiya dutifully claps. “Wow, so cool,” he says. “Congratulations.” 

Katsuki swells with pride. “I bet my quirk will be stronger than yours when you get yours,” he boasts. 

“Maybe I’ll get the same one,” Kashiya says. “Or maybe I won’t get one at all. You’d definitely be the best if that happened.” 

Katsuki feels a spark of alarm at the idea. “No, you have to get a quirk too! It won’t be fair if you don’t!” 

Kashiya shrugs. He doesn’t look like he cares. How can he not care? Quirks are so important. Everyone says so. “Mah, well, it doesn’t matter to me. It’s not like I want to be a hero anyway, so who cares?” 

“Well, I’m gonna become the number one hero when I grow up,” Katsuki says, hands on his hips. “You don’t have’ta be a hero. I’ll be strong enough to protect you.” 

Kashiya swoons dramatically, draping himself over Katsuki’s shoulder and forcing him to hold him up. “My hero.” 

Katsuki shoves him to the ground. “Shut up, idiot.” 

-- 

Kashiya has a secret, one he’ll never admit to anyone. Especially Katsuki. 

It’s not his memories of a different life, though he’d decided as he grew into them that he’d keep them to himself anyway. Hatake Kakashi is dead, and it’s better for everyone if he stays that way. Kashiya has no desire to relive that life again. No, he’d rather get to experience for the first time what it feels like to be a child and not a weapon, free of the expectations that come along with old age. 

No, the secret he’ll take to his grave is a lot less dramatic: he’d noticed their quirks forming a month ago. 

There had been a subtle change in his and Katsuki’s scents, an undercurrent of burnt sugar lingering in the air that hadn’t been there before. It resembles their mother’s scent, though theirs is stronger. On days they were particularly active recently, he’d started noticing an unfamiliar, vaguely sticky quality to his sweat that hadn’t been there before. 

He isn’t lying when he says he doesn’t really care what his quirk is or if he even got one in the first place. He’s already spent a lifetime fighting, facing the worst of humanity and coating his hands in blood in an endless cycle of death and pain. By this world’s standards, he’d be seen as a terrible person. He won’t retread any part of that path. 

Instead, he watches as Katsuki experiments with his quirk, newly dubbed Explosion, and makes no effort to try it out for himself to confirm whether his is the same. He’ll try it eventually, but for now he’ll let Katsuki revel in his newfound power and crow about getting to be the first. 

And in the meantime… he considers Katsuki’s loudly proclaimed desire to become a pro hero. He has talent. He’s smart, if a bit arrogant. They’re still four, so if Kashiya starts building up Katsuki’s combat skills now… it’s later than Kakashi had started, in his first lifetime, but it’s not too late. Adulthood doesn’t come until age eighteen in this world, after all. 

Kashiya won’t become a hero, not by his own definition nor this world’s profession. But he can help maximize his brother’s odds of survival in his future. 

-- 

Katsuki is the best. The strongest. His quirk is the best in their class. Everyone says so. 

He is. 

Kashiya is lazy. He doesn’t bother to try in class. He’s always slacking off and lying around. He’s a no-good freeloader that does nothing but hold Katsuki back. 

So how is he always one step ahead? He doesn’t even have his quirk yet! 

“Let’s see who can do more pushups,” Kashiya suggests. 

Katsuki loses. 

“Race you around the block,” Kashiya says. 

Katsuki loses. 

“I bet I can do a handstand longer than you,” Kashiya goads. 

Katsuki loses again. 

“Wanna learn how to throw a proper punch?” Kashiya asks. 

Katsuki growls. “How would you know how? You stupid know-it-all!” 

Kashiya shrugs, rocking back on his heels with his hands in his pockets. “A really cool ninja taught me how.” 

“Liar!” Katsuki yells. “Ninjas aren’t real!” 

“Sure they are! They’re just really good at hiding. That’s why you haven’t seen one before,” Kashiya says, like a lying liar. 

“Then show me where you found one,” Katsuki demands. If there really is a ninja hero around here then he wants them to teach him, not his stupid little brother. 

“They’re good at hiding, remember? So I don’t know where they are now,” Kashiya says. “Come on, come on, let me show you how to punch! You’re gonna be a hero, right? So you should learn!” 

“Fine,” Katsuki spits. 

-- 

Kashiya’s way to throw punches really does feel better. Stupid idiot. 

-- 

Katsuki is a natural leader, Kashiya realizes early on. 

Even before developing his quirk, the neighborhood kids hung onto him with starry eyes. Now, with a flashy quirk, they’re even more desperate to be part of his posse. He leads the charge with unwavering confidence and bravado. 

But no matter how much they try to get his attention, Katsuki’s focus has been on Kashiya. That’s become even more intense now that Kashiya’s training him, even if he thinks they’re just competing to compete. Kashiya’s managed to dial his brother’s competitiveness up to eleven, and Katsuki’s drive to be better than him is making implementing his stealth training regimen easy. 

But lately, he’s started noticing a shift in attitude that gives him a bad feeling. 

One of the other children comes to school with overwhelmed devastation written into his expression and a label instantly ostracizing him from the rest of the class. An increasingly rare diagnosis in a world with quirks at its center: quirklessness. 

Their classmates circle the boy like sharks scenting blood. There’s little sympathy. The boy’s become an easy target, and his visible anxiety only fuels the flames. Kashiya observes from the outskirts, eyes drifting over to their teacher, who offers the boy empty platitudes, then over to his brother. 

Katsuki isn’t directly joining in, but he’s watching intently, a delighted smile widening as Midoriya Izuku shrinks in on himself. 

That… may be a problem. 

-- 

Things stay in a holding pattern for around a month. Most of their classmates lose interest in Izuku as other things catch their attention. More kids get their quirks and become preoccupied with exploring their new abilities. Katsuki gets increasingly touchy about the topic whenever Kashiya’s continued delay in displaying signs of a quirk is mentioned.  

“It is rare to have this much of a gap in quirk presentation between twins, that’s true,” the doctor said, rubbing his chin in thought. “But little Kashiya doesn’t have any of the typical traits we usually see in quirkless children. Give it some more time – perhaps it’s simply a quirk with an unusual activation trigger we haven’t discovered yet.” 

Then Katsuki falls into a river. Then Izuku runs down and reaches out a helping hand, all earnestness and genuine concern. 

“I don’t need the help of a useless nobody like you,” Katsuki snarls, slapping Izuku’s hand away before shoving him into the water. “Who do you think you are? Huh? You’re less than nothing, Deku! Quirkless trash like you should stay out of my way!” He storms out of the river, the other kids in their group cackling as they hurry to catch up to Katsuki, who stalks into the forest without looking back. 

Izuku sits alone in the water, head bowed. 

Kashiya waits until the others are out of sight, then slides down the riverbank. Closer up, he can see Izuku’s shoulders hitching. As he approaches, Izuku looks up at him through wet strands of hair, looking utterly miserable. 

“You know, one of the strongest people I ever knew was as good as quirkless when he was a kid,” Kashiya says. His eyes droop in fond nostalgia, memories of a distinctive bowl-cut, boundless optimism, and incredible, endless determination running through his mind. “Everyone looked down on him, but he didn’t let that stop him. He didn’t let anyone tell him who he was. You shouldn’t either.” 

Izuku slowly reaches for his hand and lets himself be pulled to his feet before pulling his hand back quickly. He clutches them to his chest and shuffles back, out of reach, looking like he’s waiting for Kashiya to push him back down again. 

“I just wanted to help,” he says, despondent. His eyes water. “Why did Kacchan push me…?” 

Kashiya shoves his hands in his pockets, averting his eyes awkwardly. He’s no good at comforting others, and Izuku is especially emotionally vulnerable right now. “It’s not your fault. He’s just being an ass- er, a jerk. I’ll talk to him.” 

“No!” Izuku yelps. He scrubs a hand over his face and sniffles. “I-I don’t want him to be mad at me…” 

“Don’t worry about that,” Kashiya says. “I’ll get him mad at me instead. I don’t mind.” 

-- 

Kashiya bides his time after he catches back up to the group. Katsuki’s little posse shrinks one by one as kids break away to go home for dinner, until they’re the only two left. 

Katsuki grins at him, starting in the direction of home. “Come on, Mom’s making mabo tofu tonight!” 

Kashiya’s muscle memory may be gone, but the decades of experience his mind remembers is more than enough to overpower a barely-trained five-year-old. He sweeps Katsuki’s feet out from under him and is on him in an instant. Caught off guard, Katsuki wildly swings at his head, but Kashiya grabs his wrist and yanks it to the side. Katsuki’s forced onto his front. Kashiya straddles his waist, pulling his right arm back and up at an awkward angle. 

“What’s wrong with you?!” Katsuki barks, voice strained. His hands start popping with small explosions, a larger, more controlled one catching Kashiya’s arm before he manages to twist Katsuki’s hand so it’s facing away from both of them. “Let me go!” 

“Would you look at that,” Kashiya says flatly. “I beat you, and I didn’t even need a quirk to do it.” 

“You attacked me out of nowhere! That wasn’t fair, it doesn’t count!” 

“Sure it counts. You expect villains to give you a warning when you’re a hero?” 

Katsuki growls, managing to wrench his left arm out from under Kashiya’s knee. He swings it up as much as he can in his position and sets off another round of explosions before Kashiya manages to catch that wrist too and face his palm safely away. Kashiya grimaces at the feeling of cotton smoldering against his side and twists Katsuki’s arm further, to an angle he knows from experience will hurt. 

“Ow, ow, stop, you’re going to break my arm!” Katsuki howls, squirming. “I’m telling Mom!” 

Kashiya ignores him. “We’re stuck here until you’re ready to listen to me.” 

He waits, letting Katsuki seethe and yell and struggle until he finally wears himself out. He eases Katsuki’s arm down to a more comfortable position and lets out a breath. Good thing this is happening now, really – he’s sure an older, more experienced Katsuki will be much harder to keep down. “Well?” 

Katsuki’s teeth are grinding. “What do you want?” 

Finally. Kashiya sighs. “Why’d you push Izuku earlier?” 

Silence. Then, “He just made me mad.” 

“Why’d he make you mad?” he prods. 

“I dunno.” 

He waits again. 

Katsuki lets out another growl. “I dunno! Deku’s stupid face made me mad! He’s looking down on me, I just know it! Why do you care?” 

“Why do you want to be a hero?” Kashiya asks instead. 

“Huh?” Katsuki’s visibly thrown by the topic shift. “…I want to be like All Might.” 

It’s a predictable response, but the answer isn’t really the point of the question. Truthfully, Kashiya doesn’t really care what the motivations driving heroes to do what they do are. Here, being a “hero” is nothing more than a profession, the original definition of the word all but obsolete. Professional heroes defend the people they swore to protect. Shinobi had, in many ways, filled the same role, just in a different way. History before quirks had likely had their own organizations and terms for the work pro heroes do today, even if he hasn’t read enough of this world's history yet to know what they were. Money, power, fame, more quirk freedom, a legal excuse to punch people on the regular – if it drives them to do the job well, any answer would be fine in Kashiya’s books. But… “What do you think heroes do?” 

“Beat villains,” Katsuki says. The part of his face Kashiya can see looks like he’s trying to figure out where this is going. “They win.” 

“Do they help people? Protect civilians?” 

“…Yeah?” 

“If All Might saw a quirkless person that needed help, do you think he’d decide they’re not worth the trouble and ignore them?” 

Katsuki goes silent. 

Judging he probably won’t go ballistic now, Kashiya slowly lets go of his wrists and climbs off of him, sitting on the ground next to him. Katsuki picks himself up, grimacing and rubbing his shoulder. There’s gravel stuck to his cheek. “What about me? I don’t have my quirk yet. Maybe I’ll never get one, like Izuku. Do you think I’m useless trash too?” 

“Yes,” Katsuki snaps, but it’s without any true heat. He’s clearly sulking. 

“Then what does that make you?” Kashiya asks, his eyes curving up in a smile. “This ‘useless trash’ just took you to the ground.” 

“It wasn’t fair,” Katsuki complains. “That really hurt. I’m telling Mom.” 

“Yeah, yeah. Just don’t make me do it again.” Time will tell if he managed to get through to Katsuki, but this is probably the best he’ll be able to do for now. Kashiya lightly punches his brother’s shoulder. The movement shifts his shirt against his skin, and their eyes drop to the scorched patch on his uniform. “Ah.” 

Katsuki groans. “Mom’s gonna kill both of us.” 

-- 

After a lengthy scolding, a two-week grounding, and a month of watching Katsuki mostly ignore Izuku without taunting him more than he does anyone else (well... mostly), Kashiya finally lets sparks fly and officially gains the quirk Explosion too. 

-- 

The older Katsuki gets, the more he realizes his little twin brother is fucking Weird. Weird with a capital W. 

He never takes that damn mask off, for starters. It’s fucking idiotic. Everyone knows what his face looks like, Katsuki has the same face and everyone can see his. So why does he care? He dodges the question every time he's been asked. Even their own family can count on their hands the number of times they’ve seen him unmasked since he was a toddler. 

The idiot’s constantly late to things, too. Katsuki can’t take his eyes off him for a damn second, or he’ll wander off to – to pet stray dogs, or try to convince bookstores to sell him adult books, or kick rocks or some shit. Literally anything but do what he’s supposed to be doing. Katsuki constantly has to keep a grip on his sleeve or wrist to drag him along so they both actually make it places on time. And if you ever ask him why he was late? He’ll pull out some stupid-ass excuse that doesn’t even make sense half the time. Oh, sorry, I sensed someone talking behind my back and had to go check. The hell does that mean? And since when does he care what people are saying about him in the first place? 

And there’s the way he likes to act like some old geezer, moaning and groaning about being retired even though they literally just started middle school. Retired from what, elementary school? Pathetic. 

But the thing that drives Katsuki up the wall the most: Kashiya’s always one step ahead when it comes to a fight, even though he doesn’t train at all outside of what they do together. Katsuki learns a new strategy? Kashiya already knows how to counter it. Katsuki needs five tries to figure out a technique? Kashiya got it in two. Katsuki develops a new, badass, custom move? Kashiya offers advice on how to make his form even better. 

How. How? How does he just… know how all the time? He’s not even interested in becoming a hero. He doesn’t pick fights with anyone but Katsuki. He doesn’t research or watch videos. Not even a book. Never asks their instructors questions in their martial arts class. And still. Still he’s there constantly watching Katsuki and acting like a master imparting their oh-so-valuable advice. 

Katsuki would tell him to piss off, except Kashiya has the gall to be right most of the time. He’s not just talking out his ass, he really is that good at fighting. No matter how aggravating it is to get pointers from the laziest bastard he knows, Katsuki will never pass down a chance to improve. 

Katsuki’s been called a prodigy many times. Everywhere he goes, he’s better than everyone else. The top of the class. Number one in gym, even without his quirk. He’s one of the fastest learners in martial arts. In public, his twin doesn’t come across as anything special, never topping rankings and seeming content to be seen as average. But at home, when he goes up against Kashiya directly, Katsuki keeps finding himself one step behind. It’s infuriating. 

“How come you ranked so low in the race?” Katsuki demands, furiously dicing onions, garlic, and ginger. He sweeps the minces into bowls, sliced onions separated, and starts flying through the chicken. “Hah? You show me up at home and then act like some weak extra in public? What’s wrong with you?” 

The idiot hums, being his useless self and doing nothing but lie on the couch with one of his shitty porno books held over his head. “I didn’t feel like it.” 

“You never feel like it! Go die!” Potatoes, carrots, half an apple. 

Kashiya flaps a hand. “No thanks. Been there, done that, I’ll pass on a repeat.” 

“The hell does that mean, huh?” Chopping completed, Katsuki starts furiously washing the rice.

“What do you think?” 

“That you’re a fucking liar who can’t give a straight answer to save his life.” 

Kashiya puts a hand over his heart. “Oh, you know me so well.” 

“You’re a pain in my ass.” Rice thrown in the pot with water, burner turned on. Prep completed, Katsuki finally stalks over to do what he’s wanted to do this entire time: rip that piece of disgusting garbage out of his brother’s hands and incinerate it with a loud bang. “Stop laying around like a useless bum and go find the curry cubes!” 

Kashiya mournfully watches the ash that used to be his book drift to the ground. “I didn’t even get to their first kiss.” 

"Like I fucking care, stop reading that nasty-ass shit around me and get better taste in reading material!” 

-- 

Kashiya’s only half listening as their homeroom teacher reminds them to start thinking about their futures, before giving up and blanket assuming almost everyone is planning on trying to enter heroism tracks. 

He’s not entirely wrong. Even kids whose quirks aren’t exactly useful for combat tend to harbor dreams of making it anyway. Kashiya won’t begrudge them; this world’s society is so hyper focused on heroes that it’s only natural many kids dream of getting their time in the spotlight. Not to mention the generous compensation for those who really find success. 

It’s not a fair world, but it’s a kinder one than his previous world nonetheless. It’s not the first time he’s thought that. Children stay children far longer than most in his former life. Those who choose the pro hero course, or any other career involving some form of violence, get to make that choice when they’re older. They’re taught to prioritize non-lethal strategies and focus on saving people, not killing them. It’s not that killing never happens, but it’s the exception instead of the normal. 

They’ll still witness brutal, terrible things, true. But they won’t have to be the ones ordered to do them, to have that ugliness come from their own hands. 

Kakashi was five years old the day Minato taught him what it felt like to kill a human being. He watched people die, and die, and die, faces he knew and ones he didn’t. Enemies, strangers, friends. He’d rarely felt anything other than grim acceptance when he slit a throat or impaled a chest. He doesn’t remember hesitating, even as a young child. If he had to kill today, he knows he still wouldn’t feel much. He’d rather not, of course, but if it was necessary… well. Better him than someone else, he supposed. It’s not like it would hurt him in any new way. 

Would it have felt different if Kakashi had been older the first time he took a life? Would he care more? It’s a question he’ll never truly have an answer for. It’s better for everyone that he never again puts himself in a position where an enemy’s life is in his hands, with how easily death comes to him. 

Despite all of Katsuki’s posturing and screaming, Kashiya knows his brother wouldn’t come out the other side unaffected if he ever ended up killing someone. He’s heading down a path where the possibility he might have to is a very real one. Kashiya can’t stop him, won’t stop him, but he has to admit it worries him a bit. 

Even Kashiya, for all the way death had been second nature, didn’t come out unscathed. Even now, decades later, nightmares plague his sleep. They’re not as frequent as they used to be, but he knows he’s worried his family. Night terrors, they assume, when he claims to not remember what woke him up. He’ll never admit to the contents of those dreams, and how close to reality they really were. 

Katsuki’s cackling breaks through his thoughts. “I’ll definitely surpass All Might and become the top hero! My name’ll be inscribed on the list of top earners!” 

Sure. All Might is a bit of a stretch, but top earner? As long as his personality doesn’t cripple  him too much, then he’s got a good shot at it. He’s been gunning for a spot in U.A.’s hero department since they were kids, and Kashiya’s confident in Katsuki’s ability to make it in. 

“Oh yeah, Midoriya wanted to go to U.A. too, right?” their teacher says, completely unnecessarily, and the class goes silent for a few moments before they burst out laughing. 

Izuku hunches in on himself, stammering out justifications and getting nothing but mockery in return. Kashiya grimaces, glancing over at Katsuki to see what he does. 

Katsuki and Izuku aren’t exactly what he’d call friends. Not quite enemies, rivals, or even just acquaintances, either. Really, Kashiya has no idea what to call them. Their complicated relationship is beyond his middling ability to interpret relational complexity. They seem to exist in a constant state of mutual tension. 

After Kashiya’s intervention back when they were kids, Katsuki mostly stuck to ignoring Izuku’s existence. There were the verbal outbursts, naturally – Katsuki’s never been good at holding those in towards anyone. But any time Kashiya could sense his brother wanted to get physical, he redirects his attention to himself or, when necessary, he grabs Katsuki’s hand or arm. A friendly reminder that Kashiya was there and ready to kick his ass if he decided to try something. They’re much more evenly matched now that they’re older, but Kashiya still has decades of experience over his brother and a lot of dirty tricks up his sleeve he can pull out when he needs to. 

It had taken Kashiya a long time to puzzle out why Izuku in particular seemed to set Katsuki off so badly. When it finally clicked, he’d been a bit caught off guard by the answer. Somehow, for some reason, his brother seems to think Izuku thinks he's better than Katsuki. 

Kashiya has no idea how to fix something like that, outside of continuing to draw Katsuki’s attention to himself instead. It’s good for Katsuki to keep getting his ego checked, and it’s better for most of his ire to be targeted on Kashiya rather than a young, timid boy who’s already got the deck stacked against him. 

Now, Katsuki just scoffs loudly and crosses his arms over his chest. “Enjoy losing, you shitty nerd. Better hope you’ve got a backup school ready, ‘cause you’re gonna need it.” 

Izuku wilts further, but at least Katsuki isn’t really picking a fight. It’s not like he hasn’t already been mocking everyone else in the class with the same kind of rhetoric. Izuku’s not being singled out as the only one to get to hear it. 

“Mah, it’s not good to underestimate people,” Kashiya drawls, slumping over his desk and giving Katsuki an eye-smile. “You never know what someone’s got hidden up their sleeve. All it takes is one lucky shot. Why, even little old me has managed a couple against you!” 

Katsuki snaps, just as expected. He grabs Kashiya by his uniform and lets out a few pops next to his head, snarling and seething. “I’ll kill you! You know damn well everyone only thinks you’re average ‘cause you’re a lazy bastard!” 

Beyond used to this display, the teacher barely reacts beyond a tired, “Settle down, boys.” 

“I’m not settling shit!” 

Out of the corner of his eye, Kashiya sees Izuku watching them with a curious, if still morose, look on his face. 

-- 

Over the years, it’s become more and more common that Kashiya and Katsuki separate after school to do their own things. Katsuki has his own social group now, and Kashiya is content to spend most of his time on his own. If it means he just so happens to be picking up on information on the streets while he does it, well, no one needs to know. Old habits die hard, and all that. 

When he first hears an explosion in the distance, he doesn’t think much of it. Seems like there’s something blowing up every other week these days, and that sort of thing is no longer his business to get involved with. He shoots a quick text over to Katsuki just to confirm his location anyway, per usual. Katsuki’s used to the routine. 

There’s another explosion, then another, and another. They all sound equally distant, but that’s a little more unusual. Kashiya checks his phone. No response yet, and it’s still too recent to have ended up on the news. It hasn’t been long enough to warrant serious concern, but he starts to move in the direction of the commotion all the same. 

He won’t get involved. He’ll leave it to the active professionals. Kashiya’s retired. He’ll just take a look to make sure, and then he’ll leave. 

A news article appears on his feed, the thumbnail a grainy image of what looks like a giant mound of green sludge surrounded by flames. He opens it, scanning the text quickly. An enemy All Might had been tracking reappeared – All Might nowhere to be seen – pro heroes onsite struggling to contain the chaos – a junior high schooler held hostage. 

Kashiya has seen less than five seconds of the live footage before he’s sprinting. 

Those explosions. A glimpse of spiky blond hair. 

Katsuki. 

If his brother became a pro hero, there was always going to be the possibility his life would be cut short long before Kashiya’s. He’d known that from the very beginning, and he’d accepted it. He’d already spent a lifetime with the underlying understanding that life is transient, tomorrow never guaranteed. Every time he spent with the people he cared for could be their last, and he’d lived through a lot of those last times. 

But here, in this softer world, he’d hoped for more time. For more years where the risks were limited to civilian levels, not an active combatant’s. 

Kashiya dodges civilians and obstacles without a thought. He can hear the sound of screaming now, some people running away from the scene and others drifting closer with their phones out. Mt. Lady’s gigantic form is visible over the tops of buildings. What is she doing? The explosions haven’t stopped, but she’s not doing anything to help. 

He can see the flames now for himself, pockets of fire everywhere the evidence of his brother’s desperate fight for survival. He’s been fighting with everything he has. 

A loud, deep yell. An explosive bang far louder than anything Katsuki has ever produced. The air pressure around Kashiya warps, then blasts backwards. He throws himself to the ground before the intense force can send him flying, covering his head as debris and viscous fluid shoot past around him. 

The moment he can stand again he’s back on his feet, shoving through what’s left of the stunned and windblown crowd at the scene. 

Katsuki is crumpled on the ground behind a very familiar silhouette. 

Decades of experience have him cataloguing the scene even as he runs. The sludge villain is nowhere to be seen. All Might, not a threat. Izuku, not a threat. An unfamiliar hero moves to try to stop Kashiya, but he sidesteps their grasp and drops to the ground next to Katsuki. 

Pulse, check. Breathing, check. No visible blood. He firmly taps Katsuki’s shoulder, calling his name. Unresponsive. He turns to Izuku and repeats the same steps. Kashiya rolls Katsuki onto his side into the recovery position. Izuku is already lying on his side, so he leaves him be. 

Rain starts drizzling down. Shortly after, the crowd around them starts cheering. There’s a slight scuffing sound nearby, and Kashiya’s eyes narrow. Had All Might just staggered? He files that away for later. 

Several more heroes start gathering around them to help, and seconds later, Izuku lets out a confused moan. Shortly after, Katsuki’s eyes flutter and his arm flops to the side as his body tries to jerk back to consciousness. 

“Katsuki,” Kashiya says again, with another tap to Katsuki’s shoulder. “Hey, can you hear me?” 

Katsuki’s hand shoots up and grabs hold of Kashiya’s sleeve. He takes a deep, gasping breath and starts coughing. “M-motherfucker. You're late.” 

“Sorry, sorry. I was stuck in a staring competition with a wall,” Kashiya says, forcing some lightheartedness into his tone as he follows through with their familiar exchange. Katsuki’s going to be fine. They’re fine. “You sure put up one hell of a fight. I could hear you from blocks away.”

“Hey, kid,” a hero in white and yellow says. He puts a firm hand on Kashiya’s shoulder, attempting to pull him back without much success. “Come on, step back and let the pros handle this, okay?” 

Katsuki cracks his eyes open and growls, immediately starting to struggle to sit up. “Don’t tell him what to do.” 

“Take it easy,” Katsuya says gently, though he doesn’t hesitate to brace his brother to help him up. 

Several reporters are already starting to swarm the area, multiple cameras trained on them. Apparently deciding it’s not worth the fight to try to make Kashiya leave, the hero changes gears. “That was amazing toughness! And that quirk! Once you’re a pro, please come to my agency…!” 

They both tune them out. Katsuki glares at the ground, breathing and pulling himself back together. Katsuya gives him time, keeping one grounding hand on his shoulder. 

Nearby, Izuku gets thoroughly scolded for recklessly rushing in to help. 

-- 

Kashiya’s been different since the Incident. The day Katsuki refuses to think about. He’s fine. He’s fucking fine, and everyone else should get the memo and stop running their mouths in his direction. They can take all their worry and concerned questions and fuck off. If one more extra tries to say something about it, he might actually lose his shit. 

But Kashiya almost never mentions it. Katsuki’d half expected a whole-ass interrogation, or at a bare minimum some questions around what strategies or techniques he’d used like the tone-deaf bastard he can sometimes be. Katsuki’s shit with understanding people or how to talk without causing problems, and for all that Kashiya seems better at it on the surface, he’s actually pretty shit too. He’s just better at hiding it. 

Instead it’s like That Day flipped some kind of switch, the kind that doesn’t involve talking but sure as hell involves a whole lot else. Maybe no one else notices, but Katsuki knows him. And he watches, and thinks, because it’s easier to let his mind focus on this mystery than let his thoughts wander back to The Thing He’s Not Thinking About, Fuck Off. 

Kashiya’d always been the kind of guy who watches the room. Katsuki had picked up his habit of casing doors, windows, people, all that crap years ago. Why he does it like it’s second nature is beyond him – it’s not like Kashiya’s a formally trained fighter or been at war or whatever, but it doesn’t matter, it’s normal for him. What’s not normal is the way it’s been dialed up to eleven. 

Instead of a cursory check, now he’s checking constantly. He slouches and looks relaxed but there’s a new tension like he’s a hair-trigger away from jumping someone. Instead of fucking off to who-knows-where after school, he trails behind Katsuki, playing it off like he just felt like joining him today. Except “today” is every day. 

It’s probably some kind of paranoia or protective fear or something like that. Katsuki’s fine, and he sure as hell doesn’t need his little brother defending him like he’s some damsel in distress. It was one time, and no, it won’t happen again. But if Kashiya’s scared, then Katsuki won’t blow up on him over it. That’s what older brothers do, right? Say all you want about them being twins and him only being older by seven minutes – he’s the older brother, and older brothers watch out for their little siblings. He takes that shit seriously. 

If Kashiya can see that Katsuki’s Fine, maybe he’ll start getting more sleep again. He needs to get back out of his head and stop fantasizing about whatever worse case scenarios are running through his mind, or whatever the hell else is making him quieter than normal and spacing out in between getting all hypervigilant over nothing. 

Katsuki’s not worried. He’s not. It would just be nice to know what to do to make things go back to normal. 

-- 

Izuku has no idea what to expect when Shachan pulls him aside one day during lunch. Shachan rarely makes an effort to interact with anyone outside of Kacchan, including Izuku, so this is super weird.  

Honestly, Izuku finds Shachan hard to read most of the time. It’s so hard to tell what he’s really thinking, especially with half his face always covered up. It’s the opposite of Kacchan; it’s usually easy to tell what he’s thinking. 

Kacchan and Shachan are so different from each other. Izuku doesn’t know how Shachan does it, dealing with a twin with such a strong temper. 

They both ignore societal conventions, but in completely different ways. Kacchan’s loud, rude, and does whatever he wants whether it upsets people or not. Shachan’s calmer, quieter, but he’s constantly late, openly reads inappropriate books in public without shame, and will do things like ignore people or even walk away mid-conversation if he gets bored. Kacchan is straightforward and never hides what he thinks. Shachan lies without blinking an eye, until you can’t tell what’s true and what’s not anymore. 

Still, Izuku looks up to both of them. How can he not? Kacchan is strong and capable, and so, so confident. He knows what he wants and doesn’t hesitate to reach for it. He’s strong enough that Izuku bets he’ll make it into U.A. He’s everything Izuku had always wished he could be… minus the temper. And the mean streak. 

Shachan doesn’t show the same kind of combat ability his twin does, even though he has the same quirk. He doesn’t stand out most of the time and seems more interested in goofing off than taking things seriously. Kacchan is constantly fighting with him and yelling things about him faking it, and at first Izuku thought he was just embarrassed and trying to make it look like he’s not related to someone who’s average, but sometimes he does wonder a little bit. It just doesn’t make sense why Shachan would do that, though. Besides, wouldn’t Kacchan like being so much more talented? Whatever, Izuku could go in circles all day and still get nowhere with that train of thought. 

But quirk skill aside, Shachan has always been nice to Izuku, even when no one else was. Back when they were little, when Kacchan had shoved him in the river and called him useless trash, Shachan had stayed behind and helped him up. He’d never mocked Izuku for his quirklessness, or joined in when others ganged up against him. It doesn’t seem like he cares at all that Izuku’s quirkless. He doesn’t really do anything to stop the bullying, but at least he doesn’t hurt him. 

Or at least, that’s what he’d thought for a long time. But lately he’s started noticing a pattern. Everyone knows Shachan likes teasing Kacchan and making him get mad. He does it all the time. But sometimes the timing is really convenient, pulling the meaner kind of Kacchan’s attention off Izuku or anyone else unlucky enough to have earned it and focusing it back on himself instead. Kacchan’s fury and insults seem to roll over him like they're nothing.  

He's just so… unbothered. He never seems to care what people think or say about him. Maybe it’s because he’s actually got a quirk people think is cool, even if he doesn’t use it much. Maybe he’s just so used to it, after living with Kacchan his whole life. Izuku always wanted to be able to do that – just not care what people call him. Not care that people always look down on him, pity him, because he doesn’t have a quirk. 

When he inherits One for All… if he really gets such an amazing quirk… will he finally be able to feel that way? 

It still doesn’t feel real. All Might wants Izuku to be his successor. Useless quirkless Deku, a hero. 

He’ll do anything. Anything at all to prove All Might didn’t make a mistake choosing him. 

Izuku twitches as he realizes Shachan’s just standing there staring at him with an unreadable expression, and Izuku’s been mumbling under his breath. Again. “Uh, so, um, what is it that you wanted to talk about, Shachan…?” 

Shachan bows, which, what. “Izuku. Thank you for helping my brother when he got attacked.” 

Shachan’s almost never anything more than vaguely polite. Izuku has never seen him bow before. But now he. To Izuku? It’s not even just a polite bow, it’s a respectful bow. 

Izuku’s brain short circuits a little. He flails, stuttering. “N-no, no, I didn’t do anything, really! I was useless…” 

Shachan straightens, looking super serious. “I watched the news footage. I talked with Katsuki, too. You put yourself in danger to try to help him, even though he hasn’t been very kind to you in the past. So, thank you.” 

“He… he looked like he was asking for help,” Izuku says weakly, brain still working on coming back online. “My body just moved on its own.” 

“I’ll drag Katsuki over to thank you personally once he’s had a chance to calm down and think through what happened,” Shachan says. “Might take a little while though. You know how he is.” 

Yeah. He definitely knows. And he really doubts he’ll be getting any expressions of gratitude from Kacchan, no matter how confident Shachan is about it.. “No, no, he doesn’t have to, it’s fine. I’m just glad he’s okay!” 

Shachan shrugs. “Still. It’s something he should do..” 

“…Right, okay, if you say so.” 

“Oh, and Izuku,” Shachan says after a few moments of silence. He reaches out, pausing when Izuku flinches a little – stupid, embarrassing, obviously he’s not going to hit you, come on – before lightly patting a hand on Izuku’s shoulder. “You’re already a hero. Maybe not in the professional sense… but there’s more than one kind of hero out there. No matter how your entrance exams go with U.A., you’ve got a bright future. Don’t lose sight of that.” 

And then he leaves, and Izuku’s the only one there to witness his own tears. 

-- 

“The hell’re you doing with an application for U.A.?” Katsuki asks, looming over Kashiya where he’s sitting. “Thought you didn’t wanna be a hero.” 

Kashiya raises an eyebrow, tilting his head back to look at him. “There are departments outside of the hero one at U.A., you know. What, did you want me to pick a different school? What kind of brother would I be if I left my cute little brother all alone?” 

Katsuki snarls, explosions popping in one hand as he grabs Kashiya’s shoulder. “The hell you mean, ‘little brother'? You’re the little brother here! You askin’ for a fight, you bastard?” 

Kashiya goes pliant, letting Katsuki shake him as he holds up his hands in mock surrender. “Oh, so scary! You’re gonna terrify a whole generation of kids with a face like that.” 

“Tch! Whatever. Do whatever you want, just stay out of my way.” Katsuki gives him a last shove before stomping away, teeth grinding. 

Kashiya grins. His dear brother is so much fun to rile up. He makes it so easy. 

Katsuki will make it into U.A. There’s no doubt about it. As they’ve gotten older, Katsuki’s become formidable in combat. It comes naturally to him. He’s certain that even without himself in the picture, Katsuki would have been extremely skilled. But Kashiya’s own experience has helped Katsuki advance at an even more unmatched pace for his age. 

His eyes wander back to the application form. He hadn’t thought too much about his academic path until recently. He’d always assumed he’d go with some generic school, or if he did decide to shoot for U.A. alongside his brother, that he’d be applying for the General Studies department. He’d half considered applying for U.A. even if he had no plans to actually attend, just to tease Katsuki. 

But ever since that attack… a different idea has been formulating in his mind. He still doesn’t plan to become a pro hero. For all that he feels closer to his physical age nowadays than the number of years he remembers living, the idea of going back to a career of fighting makes him feel exhausted. Old. 

But maybe there’s something else he can do. Something to help the person he’s closest to in this world. The one who’s cemented himself as Kashiya’s most important person in this world. 

-- 

U.A.’s entrance exam. This is the moment Katsuki’s been preparing for for years. This will be the proof of his strength. He’s going to be number one, indisputably. 

He and Kashiya both took the written part of the exam a couple days ago. Katsuki aced it, he’s sure of it. If Kashiya bothered to put any effort into it, then there’s no chance he didn’t pass it too. Before Katsuki found out his brother also planned to apply to U.A., he’d had some stupid dream of his hero emergence story including the part where he was the only one out of his pathetic middle school to make it into U.A. The second Kashiya came into the equation? Whatever, forget that pipedream. No one, not even Katsuki, has ever managed to stop the idiot when he’s made up his mind about something. Kashiya will make it or he won’t, and there’s fuck-all anyone else can do about it. 

But today is Katsuki’s day to shine. Even if Kashiya makes it into U.A., he’ll only be a footnote in the history books as the new Number One Hero’s brother, with his stupid commitment to acting like an extra most of the time. That won’t look so bad – it would only make sense for King Explosion Murder’s twin to meet the bare minimum requirements of U.A.’s written exam. 

What would suck a whole lot more would be if fucking Deku makes it in. 

Just his luck, the nerd couldn’t sit anywhere else but right next to Katsuki as the Cockatoo hero screeches his explanations of how the practical exam works, so now he’s stuck listening to an endless stream of irritating mumbling on top of the hero’s shrieking voice. 

At least they’re split up when they’re actually dismissed to go start the practical. Katsuki’s left with no distractions. A deep breath, the announcer gives the signal, and he blasts forward before anyone else has managed to start moving. 

He weaves a fluid dance of acrobatics and calculated explosions as he charges through the battle grounds. Robot after robot falls to his blows. Adrenaline sings in his veins. He feels so alive. 

He barely pays attention to the others around him. He’s focused on the goal. Katsuki will come out on top. That doesn’t mean he’s completely oblivious – he can’t afford to be. He could get caught by some extra’s stray quirk if he’s not aware of their positions and actions. 

And un-fucking-fortunately, that means he notices the occasional idiot almost get themselves pulverized. Even more unfortunately, that means he has to course correct to throw them out of the way. Not like he’s gentle about it, or bothers to check in on them after he hurls them into the side of a building or down a road or wherever the hell they end up flying, but they can be thankful they’re at least not seriously hurt or dead. Probably. 

Fucking sue him, he just knows Kashiya would look at him all disappointed and shit if he didn’t help. Katsuki doesn’t give two flying fucks about all these extras, but Kashiya likes to get all sentimental and annoying about this kind of thing. Something something protecting those weaker than you, yadda yadda abandoning friends is worse than breaking the rules or whatever – and yes, that includes allies and classmates even if you don’t like them, Katsuki – ugh. Damn philosopher. 

By the time the match ends, Katsuki is panting and sweating hard. A lot of applicants drop to the ground when time is called, clearly exhausted, but he strides out of the arena with confidence. He did better than anyone else in this arena, he’s sure of it. 

-- 

Their letters arrive on the same day a few weeks later. Katsuki doesn’t hesitate to rip his open.

88 villain points. 14 points ahead of second place, according to All Might’s booming congratulatory speech. 

Katsuki had known from the second the exam ended that he’d done well. That he’d had a good shot at becoming one of the top performers. But this is even better than he’d expected. Though whoever they had tallying points apparently had shit math skills; he’d only blasted 83 points’ worth of robots. 

“I knew you could do it,” Kashiya says with a grin. His hand shoots out and ruffles Katsuki’s hair before he can stop him. 

Katsuki growls and shoves him away, snatching Kashiya’s unopened letter out of his hands in retaliation. “Like there was any chance I wouldn’t!” he barks, tearing open the letter. A disk just like Katsuki’s clatters onto the coffee table. “I’m gonna be number one someday. This was nothing.” 

Kashiya hums. “That attitude of yours is sure going to be popular, I just know it.” 

“Tch.” Katsuki smashes the play button. 

Sure enough, Kashiya got accepted too. No surprises there. The department is the surprise. 

“You applied for the Support department?” Katsuki demands. “Since when were you interested in that shit?” And then: “And since when did you know anything about mechanics or whatever the hell else they work with?” 

Kashiya shrugs, practically melting into the couch his posture’s so boneless. “Figured it would be more interesting than general studies. Who knows, maybe someday I’ll be the one making your gear. That would be fun, right?” 

Katsuki plans on being so filthy rich he’d be able to get his support equipment made by the best of the best when he’s a pro, but there could be upsides to having Kashiya involved. They share a quirk, after all, so no one’s gonna be able to understand their quirk better than the two of them. 

“Whatever. Just make sure to mind your own business at U.A., got it?” This’ll be the first time in their lives they’re in separate classes. Katsuki’s looking forward to finally not having a constant shadow screwing up his badass reputation. He’s the Bakugou Katsuki, future hero King Explosion Murder, and all those extras better remember it. 

-- 

Kashiya’s already braced for the rant before it comes. 

“How the hell did that shitty Deku make it into U.A. without a quirk, huh?” Katsuki seethes as he stomps home, clearly not in the mood to go do something after the school day. “It has to be some kind of dirty trick! He never bothered to even train for it!” 

Kashiya trails a couple steps behind him, hands in his pockets. “You sure about that? Seems to me like he’s bulked up a lot recently.” 

Katsuki scoffs. “Even if he suddenly got serious for some fucking reason, he shouldn’t have been able to do anything against those damn robots. How do you explain that?” 

He’s not wrong. Kashiya’s been pondering the same question ever since their teacher pulled the three of them aside to congratulate them on their acceptances to U.A. Izuku’s abrupt change to his training regimen – because he has to have started some kind of intense workout routine, with the amount of muscle he’s managed to develop over just a few months – seems to have started roughly around the same time where Katsuki was attacked by that villain. Had the experience shaken Izuku into getting serious? 

And even if it had, how had he managed to improve so drastically in just a few months that he managed to score high enough to get into the country’s most elite hero course, without even having a quirk to help him out? 

There’s something they’re missing. Some puzzle piece that would help it make sense, if they ever find it. Not that it’s any of their business. 

-- 

Their first day at U.A. solves that mystery and creates a new one to take its place. 

“A quirk! That liar Deku had a fucking quirk all along!” Katsuki shouts, fists popping with barely contained explosions as he paces back and forth in the empty classroom he dragged Kashiya into the moment classes were done for the day. 

Oh boy. Well, if nothing else, that explains how Izuku was able to pass U.A.’s practical exam. Kashiya pulls out a chair and straddles it, eyes tracking his brother. “What exactly happened today?” 

“Deku used a quirk to throw a ball during these quirk tests Aizawa-sensei had us do. That shit went flying the same distance my throw did! There’s no way he did that just through training! That fucker’s probably been laughing at us behind our backs for years.” 

“Hm… Izuku doesn’t strike me as the kind of person to do something like that,” he says, thinking. “Isn’t it more likely he recently found out about his quirk himself, or that he got a quirk from somewhere?” 

Katsuki scoffs and kicks a chair onto its side. “Right, because you can just go and get yourself a quirk like it’s a new pair of shoes. The hell you mean, get a quirk from somewhere?” 

Kakashi spent more than twenty years carrying a bloodline ability that didn’t belong to him, where the practice of dojutsu theft was common enough for the Uchiha and Hyuuga to have established practices to keep their eyes from falling into enemy hands. In this world, where quirks have endless presentations, it seems inevitable a way of transferring, bestowing, or otherwise activating a previously dormant quirk must exist in some form. 

Did Izuku have a chance encounter with someone? Or did he seek it out? If Izuku isn’t sharing, then it’s unlikely they’ll find out. Ultimately the truth isn’t that important. Good for him.

“I’m sure there are quirks out there somewhere that could make something like that possible,” Kashiya finally says vaguely with a wave of his hand. “Did he seem experienced with his quirk?” 

That question finally seems to snap Katsuki out of his humiliated fury. He slows his pacing, eyes flicking to the left and brow furrowing in thought. “The first time he tried to throw the ball, Aizawa-sensei stopped him and got all pissed over something. When he tried again, he fucked up his finger doing it.” 

“He’s probably still learning how to control it, then. He probably only hid his quirk for a few months at most, and I’d bet he had a good reason to.” Kashiya doubts it was just a matter of Izuku discovering his quirk so late in the game. If he had, he probably would have broken the news excitedly when he first found out. It’s much more likely whoever helped him get a quirk asked him to keep the how a secret, and Izuku had been trying to avoid people prying as much as possible. At U.A. the only people who knew he'd been quirkless were himself and Katsuki, after all. 

“It’s fucking underhanded is what it is,” Katsuki growls, but most of his former anger is missing from his tone. 

“Give your blood pressure a break and don’t let it get to you too much,” Kashiya advises. “Wouldn’t you rather think about things that aren’t your dear rival? Tell me about the rest of your day.” 

“Don’t call him my rival, he’s nothing but a shitty nuisance!” 

-- 

“Anything fun happen today?” 

“All Might had us do these mock battles. The damn roll of the dice got me stuck with Deku as one of my opponents, him and some floaty girl. The nerd wouldn’t even use his quirk until it was too late!” 

“You said it tends to injure him, so that’s not surprising. Did you win?” 

“Hell yeah, we won, obviously! I wanted to go psycho on his ass, especially once he started holding back like an idiot, but I held it in. Barely. They were no match for me.” 

-- 

The school is under lockdown. 

Kashiya’s practically vibrating with the need to do something. Power Loader was called out a while ago, the reason why undisclosed, but Kashiya can read between the lines. They’re under some kind of attack. It remains to be seen what kind of threat they’re facing, and who’s in the most danger. 

He can’t hear any sounds of commotion. Whatever’s going on, it’s probably not within the main school building. U.A.’s campus is huge – it could be anywhere. 

Just like the time Katsuki was attacked by that sludge villain, he’s not responding to texts. And if anyone was going to be targeted, it’s probably the hero students. His brother’s probably in danger and there’s nothing he can do about it. 

He’d chosen this. He’d decided to stay out of fighting in this life. But the reality of it – of knowing someone important to him is out there in danger and he’s stuck sitting around uselessly – it’s harder than he’d expected. As Kakashi, he was used to being on the battlefield. Of being one of the people fighting to protect the village and the people they care about. Even now, if he ever ran into a situation where he could make a difference, he wouldn’t hesitate. No hero license? Doesn’t matter. He doesn’t need one to take action, no matter the consequences afterwards. 

But he wouldn’t even know where to go, if he were to try to get involved now. And if the threat reaches this classroom, his classmates would be in serious danger. Almost none of them have any combat training. They have some support gear, but they’re only days into their first year of high school, with most of them having only limited experience even with their own creations. Kashiya is their best shot at making it out alive, if the threat comes to them. 

So he puts himself between the other students and the door, armed with the most dangerous support gear in the classroom and an extra layer of clothing to increase his sweat production. He ignores any attempts they make to make him back down, and he waits. 

-- 

The moment they’re allowed to leave the classroom, Katsuki’s on his feet and out the door. He’d overheard Half and Half’s assumption that the rest of the school hadn’t been under attack, but he needs to see for himself. 

USJ… it was a lot to process. U.A. had been attacked by villains. They’d barely started the school year and they’d already been targeted. Luckily most of those villains were untalented trash, but that brains creature was on a totally different level. If All Might hadn’t shown up they could have been killed. And the leader had managed to get away. 

Kashiya must have done the same thing Katsuki did, because he spots him walking fast down the hall towards him roughly halfway between their classrooms. Katsuki feels one last wave of tension release at the sight. Kashiya doesn’t look hurt. From his texts it hadn’t sounded like he’d been in danger, but he probably wouldn’t have been upfront about it even if he’d gotten pummeled. 

Kashiya comes to a stop in front of him, looking him up and down. His voice is clipped and serious. “Status?” 

Right to business. “I’m fine,” Katsuki grunts. 

“Report.” 

He rolls his eyes and scoffs. This had been one of Kashiya’s stupid lessons years ago, spouting off like some know-it-all about the importance of knowing how to give good field briefings. Now he wants to act like some kind of mission commander or some shit? “Situation’s already over, you know,” he snaps, but the hard set of Kashiya’s shoulders tell him he’s not going to drop it. “Ugh, fine. Big group of villains attacked us in one of the training buildings. Warped themselves in and split us up. The teachers arrived later, but the ringleaders escaped.” He shoves his hands in his pockets. “Couple teachers that were with us got pretty hurt, but everyone else is fine. A little banged up at most, except for that idiot Deku who busted both his legs. He’s really gotta get a handle on that damn quirk soon or he’s gonna fuck himself over for good.” 

Kashiya nods, finally losing some of that unnerving aura. Seriously, if Katsuki hadn’t literally grown up with the guy, he’d almost think he actually was a pro or something. Fucking creepy bastard. “The rest of the campus went into lockdown. I haven’t heard reports of anyone other than your class getting attacked.” 

“You would have been fine even if they did come after you,” Katsuki says, waving a hand dismissively. “Most of them were third-rate losers. Thought they were hot shit, but even the worst students in the class were able to hold their own against them. Fucking embarrassing.” 

Kashiya seems to relax a little further, his eyes curving in a smile. “And yet you still came running to check on me.” 

“Like hell I did!” Katsuki barks, ignoring the glares that earns from some of the extras passing them in the hallway. He grabs the idiot’s arm and starts dragging him along towards the exit. “I came to make sure you didn’t do something stupid!” 

“Sure, sure, whatever you say.” 

-- 

The Sports Festival was going fine. It was going great. Idiot Kashiya purposely flunked out in the first round, citing some bullshit about not stealing his thunder, as if Katsuki’s win means anything if his opponents aren’t giving it their all. He wants to win by truly being the best with everyone giving it their all, damn it, and he knows that bastard knows that too. He’s sure Kashiya only said that to piss him off – the real reason for his piss-poor performance is probably just that he didn’t feel like bothering. Like always. 

If this wasn’t such a common frustration maybe he’d be losing his shit, but instead, all he feels is resigned aggravation. Yet another hollow victory coming right up. If Kashiya won’t go all out, Katsuki’s already lost. 

It drove him insane to come in second place for the Cavalry Battle, but there was nothing he could do about it other than scream out his rage and move on. 

And now it’s not just Kashiya ruining Katsuki’s win, that damn Half and Half bastard refuses to use half his fucking quirk against him and it’s infuriating. He needs to prove he’s the best and he can’t do that when idiots go around handicapping themselves for no damn reason! 

“Not you too,” Katsuki rages, hands sparking as he faces down his opponent. Half and Half’s got a complicated expression on his face, frost creeping over his exposed skin, with no fucking flames in sight. “Don’t you go make my win even more pointless than it already is, you bastard! I’ll kill you! You used your flames against Deku, use them against me too!” 

And for a moment, Half and Half’s left side ignites, and Katsuki feels a wave of euphoria wash over him as he goes in for the kill. 

And then the fight’s over, the flames extinguished before his finishing move landed. A second loss. 

Katsuki howls, his fury overwhelming, on the verge of storming over there and try to kick Half and Half’s face in before a familiar feeling of hopelessness kicks in. 

“Damn it all,” he snarls, forcing himself to turn away and storm off the arena. He slams a fist into a mound of ice on his way out, setting off a massive boom as he obliterates it into fragments. He ignores the extras trying to cajole him or redirect him to wherever the hell the top three winners are supposed to gather and stomps right out of the stadium. 

He hasn’t cleared the parking lot before the first bastard who ruined today catches up to him. 

“Where’s mister first place heading off to?” Kashiya’s stupid drawling voice says, knocking his shoulder against him. 

“Go die!” Katsuki yells. “It’s all you and Half and Half’s fault my win wasn’t indisputable! There’s no point to it! I won’t accept it!” 

Kashiya sighs. “A win’s a win at the end of the day, you know. Your performance was fantastic. You earned it.” 

“You don’t get it,” Katsuki snaps. “I want to know I won because I was truly the best! I can’t know that when others don’t give it their all!” 

“The way I see it,” Kashiya says mildly, “on the field, a win can be the difference between being alive and being dead. If that win comes because someone else didn’t fully apply themselves, well, at least you’re alive to help someone else another day.” 

“That’s different and you know it.” Katsuki kicks a small rock and watches it fly down the road. “Fuck. At least with you I’m used to this shit. Maybe if he hadn’t gone all out against Deku I could let it go. But now I’m beneath that damn nerd again.” 

“As you both are now, I’m pretty sure you’d beat Izuku in a fight without much trouble,” Kashiya points out. “I think you’re the only one who thinks you’re beneath him. He looks up to you, you know.” 

Katsuki just grinds his teeth and keeps walking. 

Kashiya huffs out a laugh. “Well, at least you didn’t go try to fight Todoroki’s unconscious body. Looked like you were thinking about it for a moment there.” 

“Yeah, well, you do this shit to me way too much,” Katsuki snaps. “Drives me fucking insane!”  

“You sure you don’t want to go back for the awards ceremony?” Kashiya cajoles. 

“Hell no. I don’t want that damn medal.” 

“Alright then.” He sighs again, then claps Katsuki’s back. “Congrats anyway. I’m proud of you.” 

Katsuki shakes him off. “Whatever. Make an effort next time, loser. I want to win against you at full strength.” 

-- 

Kashiya pulls on Katsuki’s winter costume they’ve been working on. Winter is months away, but Katsuki has been planning out every part of his costume for ages. His warm-weather costume was the one the school prioritized, given he needed that one right away, and Power Loader agreed to let Kashiya join in for whatever else they make for his brother, since their shared quirk means he has extra insight when it comes to the details. He skips the headgear and eye mask – they’re irrelevant for what he’s testing now anyway, and a bit gaudy for his own taste. The gauntlets are the last part he straps into place. 

They’re an exact match for the gauntlets Katsuki’s currently using with his hero costume, except these absorb less sweat. A tradeoff to compensate for the cold, once winter rolls around. The challenge is getting the balance right: not absorbing too much and leaving their explosions weakened, but still absorbing enough to keep the gauntlets from becoming next to useless. 

Kashiya takes a deep breath and, with a running start, ignites a series of explosions to propel himself forward the way Katsuki likes to. He twists midair, changing directions and shooting himself upwards for a few seconds before dropping back down and cushioning his fall with a few more pops. He keeps himself moving as he sets off different kinds of blasts, testing each of the techniques Katsuki likes to use when he fights and feeling out the amount of power he has to put behind each while making sure to work up a sweat despite the cold temperature. 

He pauses and frowns, cataloguing his bodily sensations. This warmer, winter-friendly version of Katsuki’s costume is helping him sweat even more than he’d initially anticipated. He should be able to safely make the absorption percentage a bit higher. 

“Shit, this place is cold,” an unfamiliar voice complains behind him. Kashiya turns to see a boy with shaggy golden hair walking up to him, shivering dramatically. “Why would you choose this gym to train in when there are perfectly good ones with normal temperatures?” 

Kashiya raises an eyebrow. “Kind of pointless to test winter gear where it’s not cold.” 

“Oh. Ohhhh. That makes sense,” the kid says with a sheepish laugh. 

“Why are you in here if you don’t like the temperature, anyway?” 

“I saw you going in here on my way out of school and your hair color was seriously throwing me off, dude. What’s up with the dye job? And the mask? Trying something new for your costume?” 

Oh. The kid mistook him for Katsuki and hasn’t realized they’re two different people. He grins. “Something like that. What do you think?” 

The boy looks oddly touched. “You… you care about my opinion? Bro… I’m honored! Uh, well, the new look reminds me of Edgeshot. You a fan or something?” 

Kashiya’s grin widens. Katsuki’s going to be pissed when this gets back to him. “A huge fan.” 

“It looks cool as hell, dude!” the boy says, giving him two thumbs up. “Man, you must be in a good mood today. Normally by now you’re getting all shouty and sparky.” 

“I’m sure I’ll be back to normal by tomorrow,” Kashiya says. 

-- 

“Oh, your hair’s back to normal!” Dunce Face says when Katsuki enters the classroom. 

It takes Katsuki a few seconds to realize the idiot’s talking to him. “The hell’re you talking about? It never changed, dumbass.” 

“No, it was white yesterday,” Dunce Face insists, and it clicks into place. He must have seen Kashiya and, not using his brain for five seconds, thought they were the same person. 

“Wasn’t me,” he grunts, willing the idiot to shut up and go away. They’re already starting to attract attention. “Your eyesight needs checking.” 

“I saw you using your quirk, dude, it was totally you. Though you were way nicer and calmer than usual, it was so weird.” 

He’s going to kill that idiot. That guy thinks he can go around pretending to be Katsuki without consequences, hah? He can already see Kashiya’s stupid half-face laughing at him and imagines blowing it up. 

“Bakugou was being nice?” Raccoon Eyes says, giggling. “And calm? I can’t picture it at all!” 

“There’s no way,” Soy Sauce Face snickers. 

“I’m telling the truth, I swear!” Dunce Face insists. “It felt like I’d walked into some alternate dimension where Bakugou has manners! Oh, man, I wish you guys had seen it.” 

Out of the corner of his eye, Katsuki can see Deku open his fat fucking mouth. “Don’t,” Katsuki hisses, but it’s too late. 

“Uh, well, Kacchan has a twin brother with white hair,” the damn nerd says hesitantly, and the entire fucking classroom’s gazes all swing to look at Katsuki. “He must be who you met yesterday.” 

There’s a brief moment of silence. Katsuki grinds his teeth, bracing himself for the pandemonium he knows is coming. 

“You’re a twin?” Raccoon Eyes gasps. “There are two of you?!” 

“Why did you never tell us?!” 

“Nice Bakugou isn't a myth? He's real?” 

“The guy must be a saint to have spent his whole life living with you and not have gone mental!” 

“Oh man, I want to meet him now, I’m so curious what it feels like to talk to a calm Bakugou! Can you bring him here?” 

“Dude, why isn’t he in the hero department too?” Dunce Face asks. “He was as good as you with his quirk!” 

Katsuki is not letting that one slide. Sure, Kashiya was unnaturally (creepily) good at fighting, and Katsuki was used to getting outmaneuvered in quirkless hand to hand fights against him, but their quirk was the one thing he’d always handled with more ease. These idiots don’t need to know the details, though. He slams a fist on Dunce Face’s desk, letting off a loud explosion. “Like hell he’s better with his quirk than me, I’ve always been better!” 

Dunce Face raises his hands in surrender. “Okay, fine, maybe you’re better. But he was still good enough that he should have been able to get into the hero department, and if he’s at U.A. he must be smart enough too!” 

“Shachan’s never wanted to be a hero,” Deku says, shooting a look at Katsuki. Katsuki just stomps over to his desk. Who cares what that idiot Deku says now that the secret’s blown open anyway? Apparently bolstered by Katsuki’s silence, he continues. “He joined the support department instead.” 

Clothes leans over Deku’s desk. “What’s he like? Is he actually a calm version of Bakugou?” 

“He’s a lazy, lying waste of space who could wipe the floor with most of you if he ever bothered to try,” Katsuki growls before Deku can give them all the wrong impression. 

Weird Hair whistles. “Not even he gets a break, huh?” 

Deku laughs nervously. “He’s... uh, I guess you could say he’s very different from Kacchan.” 

Fucking understatement of the century. 

-- 

Look, Eijirou has to see it for himself. Bakugou’s one of his best friends in class, and it takes him this long to find out he has a twin brother? One that also attends U.A.? Obviously Eijirou has to meet him! 

And he’s obviously not the only one super curious to meet Bakugou’s other half. Kaminari and Ashido are right behind him, chattering excitedly. 

“I told you guys to get lost!”  Bakugou snarls as he stomps ahead of them. They have to walk at a pretty fast pace to keep up with him. 

“Come on, we just want to meet him,” Eijirou cajoles. “You’re our friend, and this is your twin, right here at U.A.! Who knows, maybe he’s been helping with some of our support gear!” 

“Please, please, I really really want to meet him! He sounds so fun,” Ashido begs. 

“I have to say sorry for mistaking him for you,” Kaminari adds. 

Eijirou can hear Bakugou’s teeth grinding. He must come to the conclusion that they’re not going to give up, because he finally throws his hands in the air, stomping away even faster. “Whatever!” 

They head towards an unfamiliar building. Behind him, Kaminari lets out a moan. “Not the freezer again! I about got frostbite there in like five minutes!” 

“Shut up! Wear a jacket or man up!” Bakugou yells. He straightens slightly as his attention seems to catch on something in the distance, before his voice enters full-on screaming-level volume. “Oi, Kashiya!” 

A distant figure heading for the same building stops walking and waits for them to catch up. As they get closer, Eijirou is struck by just how similar yet weirdly unrecognizable the boy – the other Bakugou – looks to the Bakugou he’s familiar with. Half of his face is covered by a black fabric mask attached to the undershirt under his gym uniform, but from what’s visible, they have the same face. The same height, same build, same eyes, same jaw, the same fluffy spikiness to their hair. Even the color, a silvery white instead of ashy blond, isn’t really that different. He’s carrying a pair of familiar gauntlets. But the similarities end there. 

Where their Bakugou – Katsuki, that is – is all sharp edges and swaggering confidence in posture, this one is loose and slumped. Eijirou’s so used to the angry slant in Katsuki’s eyes that it feels super weird to see them half-lidded without a single drop of that familiar fury. He didn’t even know Katsuki’s eyes could look like that. 

“You brought your friends with you,” Bakugou-the-second says, Kashiya if Katsuki’s yelling was any indication, and woah, it’s bizarre to hear Katsuki’s voice sounding like that. Calm, and borderline friendly. What the heck. It feels kind of like he just stepped into an alternate dimension. 

“I didn’t do shit,” Katsuki snaps. “They followed me against my will.” 

Ashido squeals, throwing her arms over his shoulders. “You didn’t deny we’re friends!” 

“Hey, man!” Kaminari says with a grin. “Sorry about yesterday, can’t believe I didn’t realize you weren’t our Bakugou. I’m Kaminari.” 

“I’m Ashido!” 

“I’m Kirishima,” Eijirou adds. “Bakugou never told us about you until today! Can you believe it?” 

Kashiya’s eyes crinkle in a smile. A not-even-a-little-aggressive smile. Wild. “That would be because I embarrass him.” 

“Damn straight you do,” Katsuki grumbles. “Well? Now you losers met him. Get lost.” 

Ashido and Kaminari burst out with a series of complaints and whining, Katsuki immediately shouting back at them, while Eijirou ignores them all to get a better look at the gauntlets Kashiya’s carrying. “So, what kind of fancy upgrades are you working on? The originals are already so cool, it’s hard to picture what else you could add.” 

Kashiya hums. “It’s not exactly an upgrade, really, more a sidegrade. Figured I’d get ahead of the game and start working on a set he could use in the winter, or if he knows he’s going to be somewhere cold. I’ve been trying to get the sweat accumulation balance right, and I wanted him to give these a try and tell me what he thinks.” 

Katsuki snatches the gauntlets out of Kashiya’s hands. “Give me the rest of it, then.” 

“So impatient.” Kashiya drops his backpack and pulls out a long-sleeved costume, which Katsuki also grabs aggressively before stalking off towards the gym. 

“What was it like growing up with Bakubro?” Eijirou asks as the rest of them also start heading over to the gym, at a much more normal pace. 

“Was he, y’know, like this when he was a kid too?” Ashido adds. 

“I feel like little Bakugou must’ve basically been a feral chihuahua," Kaminari snickers. 

“There was never a quiet day,” Kashiya acknowledges. “He’s always been very driven. But I’m glad I have him. And I’m glad he’s been able to make friends here.” 

Ashido coos. Eijirou is still trying to get used to hearing a voice that sounds just like their Bakugou’s sound so unaggressive. “Bakugou’s super manly! Once you get past the attitude he’s a pretty cool guy.” 

Kashiya eye-smiles again, looking all warm and completely different from Katsuki even with the same face. Honestly, even if their hair was identical and the mask got ditched, Eijirou doesn’t think he’d ever be able to mistake them for each other. Almost all their mannerisms are polar opposites. 

“Fair warning, it’s a bit chilly in here,” Kashiya warns, tugging on a jacket as they approach the doors. 

“Can’t we just stay out here?” Kaminari whines, but he still follows them in. 

And holy cow, Kaminari hadn’t been kidding when he called this place a freezer! Eijirou regrets not bringing a coat or something of his own, but to be fair, he hadn’t known he was going to be stepping into a place that feels like the dead of winter. He’s already shivering and it’s only been like ten seconds. “Why does U.A. even have a gym like this?!” 

“Didn’t that USJ place you guys went to have an arctic zone of some kind too?” Kashiya points out. “They simulate all kinds of different environments across their gyms to help with training for different situations.”

There’s a boom, and suddenly Katsuki is in the air right in front of them, fist aimed for Kashiya’s face. 

Eijirou shouts, jerking forward to fend off the attack, but he already knows Katsuki’s moving too fast for him to be able to do anything. What is he thinking?! Kashiya hadn’t even managed to make it to the second round in the Sports Festival, Eijirou would have noticed him if he had, there’s no way he’ll be able to defend himself – 

Kashiya sidesteps so smoothly it’s like he’d known the attack was coming, even though he’d looked completely relaxed and spaced out just a second ago. Katsuki immediately course-corrects to go at him again. This time Kashiya grabs his arm and throws him to the ground.  

Eijirou is left standing there, jaw agape, as the two get into what looks like a vicious, no holds barred brawl. He can see Ashido and Kaminari also standing in shock out of the corner of his eye. So much for not having the ability to get to the second round, it’s obvious they’re pretty evenly matched. Where the hell was this guy during the festival? 

Katsuki favors his quirk in the fight, like he always does, while Kashiya seems to gravitate towards hand to hand and evasive moves, though they both weave the two together with ease. The moment one of them manages to land a hit, the other’s retaliating with one of their own. This is the kind of fight he’s pretty sure they’re only supposed to be allowed to do under supervision, honestly. They look like they’re actually trying to hurt each other.  

“None of your dirty tricks today?” Katsuki yells, grinning wildly as he blasts in close to get a hold of Kashiya’s wrist and sends them both into the air in a frenzied series of spins. 

Turning himself along with their spinning, Kashiya catches Katsuki’s hair and sets off an explosion to the side, throwing them out of their building momentum. He lands a solid kick on Katsuki’s stomach at the same time he twists his arm to break the hold, putting distance between them. “Winning isn’t the point of this test, remember?” 

“This is crazy!” Kaminari cries, sidling up next to Eijirou.

“Imagine having to fight two Bakugous in class,” Ashido says with a shudder.  

Eijirou grins, the fight getting him all pumped up now that he’s gotten past the initial shock. “They would have made a wild combo if they’d both gone the hero route. I guess this is what being Bakubro’s sibling does for you, huh?” 

Both Bakugous hit the ground. Kashiya immediately moves into a bracing stance. Katsuki pulls the pin on one of the gauntlets, and Eijirou activates his own quirk before his mind has even processed what’s about to happen. 

A massive wall of flames erupts. Kashiya shoots into the air just before it hits. A wave of heat hits them, made extra intense by the temperature difference from the cold. 

The moment it dies out, he drops back down, rolling his shoulders. That insane blast must have been some kind of signal, because they both immediately stop fighting without saying a single word. 

“Holy shit,” Eijirou breathes. “That was so manly!” 

“You’re ruining my reputation,” Kashiya complains, looking mildly put out as he approaches. The only sign he’d just been duking it out like a madman is his heavier breathing. 

Katsuki slides the pin back into the gauntlet and flexes his hand, scoffing. “It deserves to be fucking obliterated! Who goes around trying to look average when they’re fucking not? Die!”

“That was so cool,” Ashido gasps. “You guys are amazing!” 

“Bro, why’d you go flying at him like that without even a warning?” Kaminari asks, slapping Katsuki on the back. “If you’d done that to me you would have killed me!” 

“He doesn’t need a warning,” Katsuki says, wearing his are you stupid expression. 

Kashiya sighs dramatically, slumping against Katsuki who elbows him. “See what I have to deal with? I have such a brute for a brother.” 

Katsuki clicks his tongue. “Whatever. The gauntlets are good. Thanks.” 

It’s the first time Eijirou’s ever heard him thank someone. Even Kashiya looks delightedly surprised, though his expression quickly shifts to unmistakable fondness. 

“Anything for you.”