Chapter Text
Izuku vaults over the chain-link fence, running toward the field at Aldera Junior High. At his current speed, Wormhole — as the villain had styled himself — would be there in 30 seconds. Deku’s priority is to keep him away from the civilian children.
He skids to a stop at the corner of the school’s exterior brick wall, taking a breath before he steps out into the open field.
Wormhole cocks his head at him, narrowing his eyes. “Hero Deku. So nice to meet you.” He’s about the same age as Deku, but looks older, gaunt with silvery hair. His eyes have a strange swirling effect to them, and his voice is raspy. He’d gotten on the agency’s radar after making two children disappear in quick succession, leaving their parents frantic with worry and the police Missing Persons Unit without a single lead.
Wormhole steps closer, slowly. He’s got a strange expression on his face. “Are you sure we haven’t met before?”
“Pretty sure,” Deku says, before swinging a line of Blackwhip at him.
Wormhole spins, kicks, and struggles, but Deku finally gets him wrapped around a pole, basketball hoop swinging at the top. “Got him,” he says into his radio, before Wormhole shoots a smirk at him and does something strange with his fingers.
Izuku’s hands tingle, and he looks down before a bright green flash shuts him into darkness.
**********
Izuku wakes up in a hospital bed, machines beeping above him. His head hurts, but a quick once-over shows no obvious injuries. He tries to sit up and a nurse rushes in. “Deku! You’re awake!”
“Yeah,” he says. “What happened?”
“Lie down,” she says, pushing him back on the bed. “We’re not sure what happened, actually. Looks like you might have been hit by some sort of teleportation quirk. One moment you were at the agency, and then you were gone. Katsuki was out of his mind searching for you. He found you at the old Aldera basketball court, passed out. If it was a quirk, it’s concerning that it would have reached you on agency grounds.”
Izuku’s mind races, then stops short. “What — you said Katsuki? Was searching for me?”
The nurse gives him a strange look. “Yes, of course he was. You know how he is about his bonded.”
“His — what?”
“Oh dear,” the nurse says. “Seems it may be worse than we thought. Get some more rest, all right? How’s your head?”
“Uh,” Izuku says, still trying to process. “It—hurts a little but I’m fine. I’d like to go back to the agency,” he says, trying to sit up again.
“Oh no you don’t,” the nurse says, pushing him down again, a little less gently. “I’ve heard how you are. Mr. Hawks said you’re not to be released until we get a full workup. Now take this, it’ll help with the headache and let you sleep.” She holds out a couple pills.
Painkillers, looks like, so Deku sighs, downs them, and lies back. His head is spinning.
**********
He wakes up to Uraraka, sitting in the rickety hospital chair against the wall. She looks up at him and bounces out of her seat. “Deku!” she cries. “We were all so worried. What happened? Was it a villain? How did they reach you at the agency?”
“Uh, hi ‘Chako,” Izuku says. He feels immeasurably relieved to see her, to have that bit of familiarity. “I have no idea what happened, actually. I wasn’t at the agency. I was at Aldera fighting Wormhole and next thing I knew I woke up here.”
Uraraka’s brows wrinkle and she stares at him. “Who’s Wormhole?”
Izuku feels like he’s tripped over an invisible curb, again. “You know. The villain I’ve been after for the past week? Disappeared those kids?”
“No, Deku, this is the first I’m hearing about this,” she says slowly.
“I am so confused,” Izuku says. “But, I have a feeling this wasn’t a teleportation quirk. It was something worse.” Cold grows in the pit of his stomach. “Have you ever heard of the multiverse theory?”
Ochako’s eyes widen. “Uh, I think I did read a book about that back at UA. It was only ever a theory, some rogue physicist wrote it I think?”
Izuku nods. “Yeah. I actually got super into that book for a while,” he laughs, “You know how I am, right?” (Does she?) “I read into it, and while there’s no proof, there have been some experiments done that indicate it could be possible. And… based on what you and the nurse have told me, I don’t — I don’t think this is my reality.”
“Holy shit,” Ochako breathes. “Really? Why?”
“Well, first off,” and Izuku really needs to get this off his chest, “What on earth is a bonded?”
Ochako raises an incredulous eyebrow. “What?”
“The nurse said something about Kacchan and ‘you know how he is about his bonded’ and no, I had no idea what she was talking about. So that was clue number one. And now you don’t know who Wormhole is. And you all thought I was at the agency but I wasn’t, I was at the Aldera school grounds before I passed out.” It all comes out in a rush, his confusion and need for information blending into a blur of anxiety.
“Well,” Ochako starts, “well, okay, this definitely supports your theory. Everyone knows what a bonded is. It’s when you — fuck,” she laughs, pitch spiking, “I don’t even know how to explain this except like you’re a child. When two people love each other very much…”
“They get married,” Izuku finishes for her.
“Uh, yes, well that too. But usually if they’re really close, and they’re compatible, like their alpha and omega get along, or their betas too but that’s a bit more complicated, then they complete the mating bond, and that’s a lot stronger than marriage.”
“Their… what? Alpha and omega?”
“Holy shit.” Ochako shakes her head. “I don’t… I don’t know if I’m the one to explain this to you. Maybe Katsuki should—“
Izuku freezes, trying to think of Katsuki Bakugou explaining love or marriage or whatever the fuck this was to Izuku of all people. “No,” he cuts her off. “Please go on, just tell me everything.”
She sighs and sits back down, rubbing her hands over her face. “Obviously this is a different world,” she says to herself, wonderingly. “So, basically everyone is born with a, basically an inner spirit, alpha or beta or omega. Alphas are dominant, aggressive, but also caretakers. They tend to bond with omegas. Omegas are more submissive. There’s a — mating instinct between the two. It goes back to ancient biology, when omegas were typically the ones who would bear children. That’s not always the case anymore but it surfaces mostly in sexual instinct, I guess? And betas tend to be somewhere in between, not super aggressive or yielding. They’re super supportive and stable in personality, usually. Often times they take a kind of ‘second in command’ role. I’m a beta.” Ochako looks tense and uncomfortable, like a parent trying to explain sex to an eight-year-old.
Izuku tries to gather his words. “So, in this world, Kacchan and I…”
“You’re his omega,” Ochako finishes.
Izuku flinches. He’s not sure why, but this realization strikes something deep in his gut. “No,” he says. “There’s no way. First off I’m not — submissive and yielding, I’m a hero! I’ve kept up with Kacchan every step of the way my whole life, despite what everyone said, despite what he — what he thought of me. And he would never. Bond with me.” Izuku scoffs, but it feels like a little like he’s stabbing himself in the chest.
Uraraka is nodding. “No, yeah, we know. You’re unusual like that. Katsuki was never going to bond someone ordinary. If your Bakugou is anything like ours you must understand that! He wanted someone who could keep up with him, even get ahead of him and push him to be the best. He’s always wanted to be the best and so have you! And there are biases about omegas being weak, unfortunately, but you’ve been proving them wrong from the start.”
Izuku doesn’t know what to say. This is too much to process, and he’s still not sure he believes a word of it.
“Look,” Ochako sighs, standing up. “How about I just bring him here and you can both figure out what’s going on.”
**********
Izuku can’t sleep. He lies in the hospital bed, clenching and unclenching his fingers. The nurse comes in a few more times, checking vitals. “We didn’t find any signs of drugs in your system,” she says, and “Your blood work looks good,” and “You should be cleared to return to the agency soon, but Mr. Hawks doesn’t want you working till they figure out what happened,” and “Your bonded is here to see you!”
Izuku tenses.
Katsuki barges into the room, and despite everything, Izuku almost smiles. He can’t be that different, he thinks. He looks exactly like Kacchan, wild hair and angry eyes, strong hands clenched at his sides.
“Deku,” he says, and he sounds the same, too. Harsh, but Deku hears the emotion buried within. Almost against his will, he feels his body relax a bit. This is familiar.
“Kacchan.”
“What the hell happened?” Kacchan strides up to the bed, bringing a hand up to Izuku’s face. He brushes Izuku’s hair out of his eyes. And that, that’s more intimacy than he ever gets. Izuku blinks, fighting not to lean into it.
“I don’t know but I have a theory.”
Katsuki snorts, oddly affectionate. “Of course you do. Let’s hear it.”
“There’s a theory that reality is split into infinite universes,” Izuku starts. “They branch off every time there’s a choice that could go differently. And basically, I think the villain I was fighting, he sent me into a different universe. Not—not mine.” Izuku’s eyes sting out of nowhere. Home, he thinks. How will he get back? Will he ever get back?
No. Can’t think about that.
Kacchan takes his hand away and stands up straight. “What?” he says. “What do you mean, different universe?”
“I’m not your Deku,” he says. “I’m not—an omega. In my world, we’re just both heroes. We’re not—together like that. The whole alpha omega thing, it doesn’t exist.”
Katsuki narrows his eyes at him, baffled. “What do you mean doesn’t exist? What do you do, then?”
“What do you mean?”
“Like, how do you bond?”
“The bonding thing doesn’t exist either. I mean, we do have—relationships, people love each other obviously. They usually get married if it’s a long-term thing.”
“But how do you know if you’re compatible?”
“You just… figure out if you like each other, I guess? And then you date and see how it works out?”
Katsuki shakes his head like he’s trying to get something out of his ear. “What the fuck,” he says. “So you don’t scent each other?”
“What?” Ochako hadn’t mentioned that. “No.”
“How do you — you know what, never mind. Let’s get back to the agency. Hawks is gonna want to hear this.” Katsuki grabs him by the arm, tugging him out of bed. “The nurse said you’re good to go.” He puts a hand at the small of Izuku’s back, and it feels so natural that Izuku doesn’t even think about following.
**********
Hawks pinches the bridge of his nose. “Hold on. From the top. Let me get a chronological account of events.”
Izuku sighs, and repeats himself. “I was pursuing this villain called Wormhole…”
He continues the story, with periodic interruptions from Hawks for clarification. Katsuki stands by the door like a guard, arms crossed, face tense. Normally Izuku would wonder why he was even present for this kind of debrief, but considering the circumstances… maybe this is normal. He has no idea.
“So,” Hawks says finally. “If this… Wormhole sent you here, and our Deku is gone, it seems likely he made some sort of swap, and our Deku is in your universe.”
Izuku freezes. He hadn’t even thought of that. But it makes a frightening amount of sense. “Uh, actually, yes that seems likely, but we really don’t know anything about Wormhole’s quirk. He was a new villain and all we knew was that he made some children disappear. Now, I’m guessing he probably sent them to different universes too. Ugh. Is there a version of him in your universe? How can we reverse this?”
“That’s the question, Midoriya. If he sent you here, then he must be able to send you back, and bring back our Deku. But we don’t know of any villain with a quirk like you’re describing.”
Izuku’s heart sinks into the pit of his stomach. There has to be a way. He can’t be stuck here forever, away from his family, his friends, his Kacchan — even though he’s not his, not like Kacchan in this universe — ugh. He can’t think about this.
“For the meantime, I don’t want to bench you, but I probably should.”
“What—no!” Deku looks up at him wildly. “I want to work. It’s probably gonna be the best way to find out if Wormhole exists in your universe, anyway!”
Hawks purses his lips and glances at Katsuki, standing in the corner. “In your universe, are you and Bakugou at least partners?”
“Like hero partners? No, but we do work for the same agency.”
“What exactly is the nature of your relationship with Bakugou, in your world?”
“Uh.” Izuku flounders. Where to even start? “We’re—friends, I guess.”
“You guess.”
“We’ve known each other since we were kids. We kind of — became rivals for a while? But now we get along, mostly.”
Hawks raises an eyebrow, smiling faintly. “So, not that different, then.”
“What?”
“Never mind. Would you be willing to act as Bakugou’s hero partner for your time here? Take direction from him, since he is the one with knowledge of our world.”
“That—shouldn’t be a problem,” Izuku says.
“Great. In that case, you are clear for limited duty, as long as you are partnered with Bakugou at all times.”
“Awesome! Thank you so much!” Izuku says, standing up and reaching out for an awkward handshake.
“One more thing. Where do you live, in your world?”
“Uh. I have an apartment on Route 521.” Shit. His apartment probably didn’t exist in this universe.
“Okay. You can either stay with Bakugou, where our Deku lives, or we can offer you a place in the Agency barracks.”
Izuku hesitates.
Katsuki uncrosses his arms, crackling a bit as he steps forward to the desk. “He’ll stay with me. Come on, Deku.”
Izuku looks helplessly between the two of them, and then shrugs. “Okay,” he says weakly, and follows Kacchan out of the room.
**********
Izuku may have made a gross miscalculation.
Living with Kacchan — this Kacchan, who is Izuku’s bonded, Izuku’s alpha — being hero partners with him — it was all too much.
Kacchan is fighting a villain with an electrical quirk when he looks up and calls to Deku, who is watching from the rooftop for the best place to jump in. “Get down here,” he says, and the next thing Deku knows, he’s shoving the villain to the ground, holding him down for Kacchan to handcuff him. Kacchan grins at him and Izuku feels high with it. “Good job,” he says, low, and Izuku feels something warm spread through his gut.
He’s washing a bowl out to make some instant ramen at 1 AM when Kacchan walks into the kitchen, sweatpants slung low on his hips.
“The fuck are you doing?” Kacchan says, voice raspy from sleep.
Izuku turns. “Just making some ramen.”
Kacchan narrows his eyes, and suddenly he’s boxed in against the sink, Kacchan’s strong arms on either side of him. “Is that what you usually eat, in your world?” he says, into Izuku’s ear.
“Uh. Yes?” Izuku squeaks.
Kacchan huffs and steps away. “Sit down,” he snaps.
Izuku sits on a stool at the kitchen counter, trying to consciously lower his heart rate.
Kacchan whips up a fresh stir fry for him at 1 in the morning, fragrant with garlic and ginger. “Low on the spice, since I know you can’t handle it,” he smirks, handing him the plate, and part of Izuku wants to protest, but a bigger part wants to roll over and kiss him.
Fuck.
And maybe that’s allowed, in this world. He never could have that, with his Kacchan.
“Kacchan,” Izuku says, finally, around a mouthful of rice.
“What?”
“Why are you doing this?”
“Doing what?” Katsuki scrunches his face at him, and oh no, it’s adorable. He actually looks confused.
“Treating me like—“ he runs out of steam, realizing he doesn’t even know how to explain this. “I dunno. Like you like me?” Wow. That sounds pathetic.
“‘Cause I do like you, obviously.” Katsuki snorts. “Dumbass.”
“But—“
Kacchan’s sharp eyes soften. “Izuku. I know I’m not your Katsuki. And you’re not my Deku. But we’re obviously still the same people. And I bet your Kacchan was pretty mean to you for a while.”
Izuku looks away. “Uh huh.”
“And maybe he’s a fuckin’ idiot who hasn’t figured it out yet, but he probably likes you too.”
Izuku gives him a self-deprecating laugh. “I doubt it.”
“Shut the fuck up with that. My Deku was the same way. And he better be okay or you’re getting the short end of it.”
Izuku looks up.
Kacchan shakes his head. “Anyway. I’m not tryin’ to cross a line here, or whatever. But you smell like him.” He walks over, like a predator trying not to scare away his prey. Puts his hands on the countertop, next to Izuku. Leans in close. “You feel like him. You act like him.”
His voice feels like it’s vibrating through him. “You say you’re not an omega, but you feel like you’re mine.”
Izuku can’t breathe.
Kacchan steps back. “Tell me I’m wrong,” he challenges.
Izuku swallows. “I—“ he starts, and his voice cracks. “I don’t know.” The words start to spill out, helpless. “I don’t—I’ve always felt like that, with you,” and wow, way to go straight for the most embarrassing thing he could possibly say. “And obviously, alphas and omegas and shit don’t exist in my world, so I don’t know how to explain that.”
“You are an omega.”
“What?”
“If you weren’t you would smell different. You are.”
“No.” Izuku shakes his head. “Like I said. That doesn’t exist in my world.”
Katsuki takes a breath, looking up at the ceiling. “Look. Izuku. Tomorrow let’s get you a blood test. That’s how they tell these things, in this world. It’s biological.”
“I… okay. I guess? Okay.” Izuku nods. It would answer some questions, anyway.
“Great. Now let’s get some sleep.”
Izuku curls up on the bed of blankets Katsuki had made him in the corner of his own bedroom. Wraps an arm around the pillow and lets his mind wander. It was so comfortable, all piled together messy like a nest. Nothing like the rest of Katsuki’s house, not neatly made like his own bed. Kacchan had done this for him. Because he didn’t want Izuku to feel uncomfortable, like he had to sleep in Kacchan’s bed just because this world’s Deku did.
Fuck.
Kacchan was always so abrasive, so aggressive. But then he went and did things like this. Made Izuku dinner at 1 in the morning. Built him a nest to sleep in. Is that what alpha Katsuki was like?
Was it so bad that Izuku wanted him? Down to his guts, down to the tips of his toes. This was what he was running from. If he closed his eyes and let himself feel, all he wanted was to climb into Kacchan’s bed and stay there forever.
He lets himself imagine it. His own Kacchan, smirking at him. Shoving him into a chair in his kitchen. Cooking for him. Holding him down at the end of a sparring session, eyes fiery. Holding him down in his bed—
Izuku squeezes his eyes shut, takes a deep breath, and forces himself to stop thinking.