The first time he uses his quirk, it's with his mom. It makes sense, Izuku thinks later; she's his home, a constant source of support and worry and love that makes him feel braver when he's around her.

She's been crying a lot lately, though she usually tries harder to hide it from him. Her hands are steady, this time, despite the tears welling in her eyes.

The salve she's applying hurts even worse than the burns do, but Izuku tries to smile at her. He's already cried once today, curled up on the bank of the shallow pond as Kacchan walked away.

It falls flat on his face no matter how hard he tries.

Izuku doesn't understand, but Mom does, must from the way she looks at him, heavy and fearful. Doesn't understand why she looks at him with such guilt, nowadays, when he's just a "late bloomer", the doctors said, weeks ago. Doesn't understand the hatred on Kacchan's face, ugly and twisted, when Izuku had reached out to help him up. The way he'd looked at Izuku like one of the worms they used to dig up for fun, just before blowing him up.

He wants to understand and he wants to make her stop crying; but he doesn't know how to do either, so instead he just reaches for her, willing himself closer, and-

-and the light that flares between them is too bright, his stomach twisting in a way he's never felt before and his mom is saying "Izuku!" and he moves to protect her, because that's what heroes do-

-she's sorry, she's so sorry, Izuku-

The light fades, and they blink their eyes.

A hands raises, instinctive, and they freeze. The room swims; they are assaulted, suddenly, with a sense of wrongness, their gaze simultaneously too high and too low for comfort.

They begin to shake. Fear is beginning to make their head buzz. This is their home, they know this with a bone-deep certainty; next to them sits a stool with one leg lower than the rest, a relic from her college days and the carpet below is soft under their feet, a slight stain burned into the fibers where Kacchan had spilled juice one day and he'd promised not to tell.

They're not Inko/Mom and they're not Izuku. When they flex their left arm, trembling, another shifts within the same socket, flexing to match it. One has had the skin near burned off at the wrist, an identical pattern to Izuku's. Something shifts, whispers in the back of their mind.

They push themselves to their feet and nearly fall. They don't look at the tan, freckled (third, wrong) hand that clutches at the table, supporting them.

The world rolls beneath their feet when they step, center of balance

When they look up, their eyes (only two, two eyes two legs three-) catch on the mirror Inko keeps hanging on the wall, and the breath leaves their lungs. They recognize the curl of their jawline, the softness of their eyes, could pick them out of a lineup of hundreds.

And suddenly, they understand.

The knowledge of who they are what this means leaves them staggering, a rush of too many emotions to identify humming in their chest, Izuku and Inko/Mom and whoever they are now that they've been combined, love-fear-worry-joy-hope-relief.

He has a quirk.

He spends weeks afterwards simply experimenting and recording, recalling every emotion and sensation he can from merging to when he and his mom had broken apart (defused?), interrogating her every spare second he can.

She's happy to tolerate his questions, demeanor lighter, more joyful in the wake of the reveal of his quirk. She cries less often, though she'd sobbed for what seemed like hours after they'd disconnected in another flash of light, holding Izuku close.

She buys him a new notebook at his request, just for notes on his quirk. He's so excited he almost shows it to Kacchan before he remembers that Kacchan's ignoring him.

For someone who'd reacted so quickly to the idea of Izuku not having a quirk, Kacchan reacts to the revelation that he does with a disappointing lack of enthusiasm. Izuku babbles about it the moment he gets to school the next day.

Kacchan looks annoyed, mostly, and tells him to shut up and draws sparks on his palms. He thinks for a few minutes when Izuku does, brow drawn low.

"How're you supposed to be a hero with a quirk like that?"

Izuku's mind staggers to a stop. He'd been so focused on the novelty of having a quirk that he'd assumed it was a given- he had a quirk, he could be a hero. Now he flounders, thinking furiously.

"I-" and he hesitates. "If I could fuse with someone strong, I could fight." Like All Might, he knows better than to say.

A familiar smirk spreads Kacchan's face and dread drips in Izuku's stomach, excitement draining out and leaving behind a cold, hollow feeling.

"Who'd want someone like you dragging them down?" he says, and the other kids gathered round laugh. "All the time you spend following me around, figures a leech like you would have a quirk that's as useless as you are."

Kacchan shoves at him, then, and all Izuku can do is stare, vision going blurry through tears.

"Aww, you gonna cry, Deku? Why don't you go cry to your mom, then? Since she's the only one who likes you, anyways!" More laughing, and the group moves on, settling loudly into the classroom.

He'd thought-

Well. He'd thought that it would be enough, having a quirk, for Kacchan and everyone else. He'd had this idea, that once he got a quirk it would prove that he wasn't- worthless, or weak, or whatever else Kacchan called him, and they could be friends again. He was wrong, apparently, and as much as that hurts, he at least has something else he can focus on now.

Izuku wipes at his nose and resigns himself, once again, to being friendless.

Their interaction, at least, raises plenty of new questions for him to consider over the next few months. What can he do with his quirk? He devotes half of his new notebook just to theorizing on what fusing with different heroes would look like, going lightheaded with excitement several times. He nearly passes out when he gets to All Might and has to quickly move to a different hero.

If he could only figure out how to use his quirk, he could study it properly.

Physical contact isn't enough- Izuku hugs his mom, over and over, even dares to press a few fingers against the skin of another student at school when he passes Izuku a pencil. No dice.

Can he use it on someone other than his mom? He hopes so; he's never heard of a quirk that only works on a single person, so he's not too worried, but the thought festers in the back of his mind. The problem is, until he can identify exactly what drives or starts the melding process, he can't test it.

It's like he told Kacchan: if he can use his quirk on anyone, he has a chance at being a hero.

A few near misses happen, which make for good data but leave Izuku nearly weeping for frustration. His mind wanders and the light fades, and whoever it was they formed last time disappears, leaving just him and his mom, fingers interlinked.

She makes him his favorite dinner on the nights when that happens, and pets his hair soothingly, eyes sympathetic and mouth full of reassurances.

"These things take time, Izuku- even All Might had to learn how to use his quirk at your age, I bet," she says.

Well, obviously, though the idea of All Might being as small as Izuku (what was All Might like as a baby All Might was a baby) gives him pause.

She taps her fingers against the table on one such night, quiet and looking thoughtful. "Izuku," she says, "what exactly do you do you're trying to activate your quirk?"

"Um." He thinks about it for a second. "Mostly I just focus on how much I want it to happen, and imagine it happening…?"

Mom worries at her nails and considers him. "Well, I'm… goodness knows you've probably read more about quirks than I have, but I was researching these things a bit, recently. Have you ever heard of the 'Quirk Factor'?"

"A few times, but… the books weren't really clear about it?"

She nods, looking unsurprised. "Well, it's what allows us to use our powers, correct? It's something all of us with quirks have, and something we all use. I was thinking, Izuku, that of all the heroes I've seen and all the people I've met, none of them had quirks that just… happened."

She's speaking a little fast now, voice smoothing in the way it does when she goes into 'teacher mode'. "Our quirks are a part of us, Izuku, and your quirk is the same way. Every person has some way of controlling their quirk, a way to make it stop or start when they need it to. It's like an arm or a leg- you can't expect your quirk to happen, or your leg to move, just because you hope it does."

He stares at her, mind whirling, and his mom blushes. Her smile is soft as she begins to clear the table.

"You're smart, Izuku, certainly smarter than your father and I were at your age. I know you'll figure it out." She kisses his forehead and walks away, a few dishes rising gently into the air and following her into the kitchen.

Izuku feels exceedingly dumb for the next few days and makes up for it in his fervor to do more research. Online forums (with his mom's supervision) are a goldmine, people flooding into online communities with descriptions of their quirks and the ways they've tried to control them.

More often than not the posts are clumsily written, pre-teens or young children describing accidentally breaking things or hurting other people or hurting themselves and frantically asking for advice. Sometimes they're written by a (supposedly) concerned parent, trying to find some sort of help for their child after disastrous attempts to control their quirk. They're riddled with typos and poor grammar and the occasional inappropriate question, which Mom carefully guides the page away from as Izuku covers his eyes.

They're perfect, as far as Izuku is concerned, because they're from the point of view of people like him, not like the books or reports written by adults who already understand their quirks.

Visualization is a common theme among the answers he finds; so is using physical triggers, like muscle flexing, though that doesn't seem very applicable to Izuku's situation.

He focuses on the light, because it always seems to appear when he comes close to using his quirk, and because it's easy to imagine. He holds his mom's hand and concentrates, picturing it: bathing his skin; forming a shield around him; being pulled out of his core.

Nothing. Izuku enjoys experimenting as much as the next person, but he's beginning to get disheartened. His mom's starting to become worried too, he can tell, from the way her face scrunches up.

They're in the grocery store, one day, fingers tangled together when Izuku stumbles on it.

(Mom has been incredibly accommodating these past few weeks, working just as efficiently as ever despite Izuku constantly holding at least one of her hands hostage. He writes a note to himself in his journal to make her a really nice card for Mother's Day.)

This time Izuku concentrates on his fingers, imagines the light extending from them like claws or ligaments, reaching out towards his mom-

-and the light answers, this time, and reaches with him. His stomach pulls and his eyes burn, just a little for the light wrapping around the both of them and he's done it-

It's just them, then, hands clenched tight on the grocery cart and the old lady nearby in the fruit section observing them curiously before moving on. (The lady herself has skin the color of mulled plums; in today's world, it's reasonable for them to assume that they're far from the oddest person she's seen, three arms and all).

They raise a hand and oh, they bask for just a moment in the pride-love-relief they feel, eyes fluttering closed with happiness at the dance of artificial lights and freckles across their fingers, warmth bubbling up in their chest and spilling down all five limbs.

They raise a hand and (Inko, at least, knows how to do this, even if Izuku doesn't) focus and pull.

Granny Smith, they think, because Izuku likes the sour taste and Inko will want to make something special for tonight, apple pie for celebration-

They raise a hand, and a single apple on a nearby shelf rises, gently, and floats towards them.