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Katsuki is six when he sees Deku crying at the park.
This isn’t particularly surprising, since Katsuki sees Deku at the park all the time and at least half of those times he ends up crying, snot dribbling down the front of his face and wiped on his dirt-stained, hero-themed sleeves. Katsuki had been half convinced the stupid nerd would dehydrate by now, what with all the sad-mad-happy tears, but the old hag insisted that’s just not how Midoriya’s work.
Katsuki still has his reservations.
This time, though, Katsuki stops walking when he sees Deku crying at the park because Deku isn’t crying alone. There’s a little blond girl next to him and a bloody bird lying very, very still in between them.
It doesn’t take a genius to figure out what happened (and Katsuki is nothing if not a genius).
He’s not sure why the girl is crying, though.
And Katsuki is nothing if not curious.
“Who the heck are you?” Katsuki demands as he steps closer, the stick he’d picked up on his way home poked aggressively into the dirt like a knight setting aside their spear.
“Kacchan!” Deku exclaims, hiccuping. “She- she ated the bird!”
Katsuki’s eyes widen, morbidly curious.
“I did not!” the girl shouts, wiping at her own stupid tears, and now that Katsuki’s looking at her a little closer, he notices the small smear of blood near her chin, the pointy teeth practically sticking out of her mouth, and the matching puncture wounds on the bird’s neck.
“It was just s-so pretty,” the girl continues. “I loved it!”
Again, Katsuki has his reservations, but he doesn’t really care if this girl loved the bird or not because her teeth- which is probably her quirk- is weird and interesting and Katsuki wants to know if there’s more to it than a couple of overgrown canines.
“Deku, stop crying,” Katsuki commands, unsurprised when the boy tries and fails to still the quivering of his bottom lip.
Katsuki turns toward the girl instead.
“What’s your quirk do?”
The girl blinks up at him, surprised, and then she starts melting and it’s the coolest thing that Katsuki's ever seen since Tuesday, when he passed an elephant man on the train. Other than himself, obviously.
She gets smaller and smaller and then she’s…a bird. The same one that’s dead on the grass.
Deku stops crying.
“Woah,” he says at the same time as Katsuki, both of them leaning closer to the girl-bird.
“Kacchan,” Deku says, reaching out to tug on his sleeve. “She’s a bird now.”
“Duh,” Katsuki shoots back. “I can see that.”
“Do you think she’s stuck like that?” Deku asks nervously.
Katsuki swats his hand away. “I thought you didn’t even like her? Why do you care?”
Deku gasps. “I don’t want her to be stuck, Kacchan!”
Kacchan rolls his eyes, already imagining which shoebox he’ll take down from his closet to make a nest for the girl-bird to bring into show-and-tell when she melts again, except this time she grows bigger.
“You’re back!” Deku exclaims happily. “I was worried.”
Katsuki frowns, disappointed.
“Where the hell did your clothes go?”
Deku eeps and covers his eyes, like he didn’t even notice until Katsuki pointed it out. The girl doesn’t really seem to care, even if she cringes under the question. Katsuki hopes she isn’t actually a crybaby like Deku and that the tears with the bird were just a one-off kind of thing.
“Um, it’s my quirk,” the girl-not-bird says. “My clothes always go away.”
“That’s lame,” Katsuki observes.
“Kacchan!” Deku scolds, hands still held over his eyes.
“Whatever,” Katsuki says, “you can come to my house to get clothes I guess.”
And maybe if she turned back into a bird on the way there Katsuki could still bring her in for show-and-tell.
“Oh, Kacchan’s house is the best!” Deku tells the girl. “His TV is this big and you can see all of All Might’s coolest fights since they’re all recorded!”
Katsuki starts walking home and doesn’t bother turning around to see if they’re following. He knows they are. Katsuki’s house is the best.
Still, “Stop bragging about my house, Deku,” he says.
“But it’s so cool!” Deku defends. “There’s All Might!”
“Yeah,” Katsuki agrees, mouth tipping into a smile.
“Who’s…All Might?” the girl asks hesitantly.
Katsuki screeches to a halt, whipping around to stare at the girl, aghast.
Deku’s expression mirrors his own.
“What…did you just say?” Deku asks.
The girl crosses her arms, eyes narrowing defensively as she looks between the two of them. “Who even cares,” she eventually bites out. “I’m sure loads of people don’t know about him.”
“No way!” Deku shoots back. “Everybody knows All Might! He’s the best!”
The girl looks like she might start crying again.
Katsuki frowns, annoyed.
First, she turned back into a girl before Katsuki could bring her in for show-and-tell and now she doesn’t even know who All Might is? Ridiculous! Katsuki didn’t even know why he was bothering with her.
Katsuki continues walking home. Deku and the girl continue to follow him, Deku talking a mile a minute about all of All Might’s best fights and catchphrases.
Katsuki listens in like Deku is a mildly interesting radio show, mostly to make sure he doesn’t get any of the details wrong.
He doesn’t, and this makes Katsuki smile for a second before he bites it back down. He doesn’t like Deku. The day at the river was the end of their friendship and Katsuki intends to keep it that way, so when he stands on his tippy toes to unlock the door he lets the girl through and stops Deku with a hand on his chest.
“Why are you still here? I didn’t invite you, Deku.”
Deku smiles. “‘Cause Kacchan’s house is the best!”
Then he slips underneath Katsuki’s arm and into the foyer like a damn intruder.
“Stupid loser,” Katsuki complains, even if Deku did have impeccable taste in houses. He’s still a trespassing criminal and Katsuki hates him.
“Oh Izu-kun! I haven’t seen you in ages!” the old hag exclaims happily, because she’s on the wrong side of Katsuki’s war against Deku.
“We found a girl who can change into a bird!” Deku tells her.
The girl is still standing nervously by the shoes instead of exploring Katsuki’s very cool house like he expected her to.
Katsuki stares, eyes narrowing suspiciously.
“You’re not actually a crybaby, are you?”
The girl frowns.
“No,” she defends hotly, “I’m just…waiting.”
“For what?”
Her face turns red.
“None of your business!”
Katsuki decides immediately that he doesn’t like this girl. Even if she turned back into a bird right this second he probably wouldn’t even want to bring her in for show-and-tell because he could definitely find something way cooler and way less annoying to bring. Like his own damn explosions.
“Okay kiddos,” the old hag says, sweeping into the entryway with a blanket to toss over the girl's pale shoulders, Deku toddling after her heels. “Let’s stop shouting and get dressed, okay?”
The girl seems to shrink down a bit beneath the blanket, like she’s nervous again, and Katsuki doesn’t understand why. The old hag didn’t even yell or call her a brat or anything!
“Brat,” the old hag says, looking at Katsuki.
Katsuki scowls.
“Go pour some water cups, okay? Three of them.”
“Fine,” Katsuki pouts, stomping towards the kitchen. One cup for Katsuki, one cup for the old hag, and one cup for whoever annoyed him the least. Deku followed Katsuki into the kitchen, trying to help, and Katsuki swiftly decided that the girl would get the third cup and Deku would be kicked out.
He reevaluates his decision when the girl comes back down the stairs wearing Katsuki’s 17th favorite All Might shirt.
The old hag must catch his betrayed expression because she walks closer to swat the back of his head.
“You don’t even fit into that one anymore,” she reminds him, taking two cups of water and handing them to Deku and the girl.
“Traitor,” Katsuki mutters, hands firmly gripped around his own water cup because like hell if he was gonna be the one kicked out of the conversation. Then his mother reaches for her half-finished mug of gross-smelling coffee and Katsuki realizes that he miscalculated.
No one is being kicked out. In fact, Deku and the girl are being invited to stay for longer.
Ugh.
Katsuki takes loud sips just to be obnoxious while Deku tells the story of what happened at the park- both before and after Katsuki got there- and the girl reveals that her name is Toga and it’s a rule that she can’t go back home until after the sun is down.
The old hag frowns at that and Katsuki drinks a little less obnoxiously because that’s a really weird rule and he wants to know if the bird-girl turns into something else at night and has to be kept in a special room like the werewolf villain on the 72nd episode of All Might’s Adventures: The Animated Series.
The truth, he finds out a few days later, is way less cool and sparks a weeks-long conversation about how some parents don’t want to be parents and are mean to their kids, especially when they have quirks they don’t understand or don’t have quirks at all. Katsuki understands this to mean that Deku and Toga are like the runts of the litter, and that’s why Deku always tries to cling onto Katsuki- the strongest- and that Toga will probably be that way too once she realizes how amazing Katsuki is.
After a month, his dad explains that they’re going to adopt Toga. Katsuki has never heard this word before in his life and he’s not sold on the idea once he learns what it means because Toga has not realized how amazing Katsuki is. She’s always trying to drink Deku’s blood and making him cry and then tormenting Katsuki with two Deku’s at the park- even though he always knows which one is the real Deku- or turning into his mom and trying to ground Katsuki for saying mean things to her.
Katsuki always knows it's Toga, but sometimes they argue so loud that he gets real grounded and Katsuki is not amused.
Sisters suck, he decides.
The worst part, though, is that she kept Katsuki’s 17th favorite All Might shirt and always manages to find it after Katsuki steals it back from her.
(Katsuki suspects she’s being helped by the old hag)
“How about I buy you a new one that actually fits?” Katsuki’s old man offers, after Katsuki’s sixth thwarted attempt to reclaim what is rightfully his.
“Then we’d match,” Katsuki complains, making a face of complete and utter disgust.
“Is that such a bad thing?” the old man asks.
“Yes,” Katsuki seethes, “because I hate her.”
Katsuki’s father hums, taking a slow sip of his less-gross-smelling coffee. “You say you hate Izuku, too, but you still carry around that card you boys got together.”
Katsuki’s eyes widen.
“That’s a secret!” he hisses.
Katsuki’s father raises his arms in surrender, then mimes zipping his lips closed. “I won’t tell a soul,” he promises, proving that the lip-zipper is a complete and total lie. “And if we go get you another one of those shirts, which you don’t ever have to wear so you don’t match, I won’t tell a soul about that either, son.”
Katsuki thinks the offer over for a moment, weighing the pros and cons in his head and also the new information that his father knows about the All Might card he keeps in his right pocket.
But the old hag doesn’t know, or else she’d be all over his case about it with her horrible witchy laugh, so maybe his father could be trusted even if his zipper-lips were fake.
“Fine,” Katsuki says. “But I still hate her.”
His father shrugs. “Maybe one day you won’t.”
“Maybe you’re delusional,” Katsuki shoots back. “That’s like saying one day me and Deku will get along.”
The old man chuckles as he reaches for his coat, patiently waiting for Katsuki to double knot the laces on his All Might shoes.
“The world works in mysterious ways,” he says.
Katsuki doesn’t really know what that means, but he doesn’t really think it matters anyway.
And if they pick up a bright pink mug with a cartoon vampire on it while they’re out, to be placed next to Katsuki’s All Might mug and the hag’s red one and the old man’s purple fish one, then nobody has to know Katsuki was the one who pointed it out.
Because sisters were gross and he hated them.
(And he and Deku were never, ever going to get along).