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DoS+BNHA Crossovers: Yesterday Upon the Stairs Verses

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Toshinori slumped, the last vestiges of One for All's strength gone from him, his duty unfulfilled. All for One yet lived, and there was nothing he could do to help Izuku with it now.

"You were right that it was time to finally settle this, All Might," the villain sneers, stalking closer to the slumped former Hero with the unhurried grace of someone who knows he has already won. "But I'm thinking this hasn't been settled in the direction you would have hoped."

All for One stands over Toshinori, arm growing and pulsing, ready to deal the final blow.

"Goodbye, Yagi Toshinori."

The arm slams down, Toshinori knows this is the end, and then-

A slight body interposes itself between him and All for One, blocking the fist with a thundering clap, but not yielding beneath its incredible power.

Izuku-? Toshinori thinks for a brief moment in terror.

But no. The girl in front of him is about the same size, and likely age, as his young successor, but that is where their similarities end.

This young woman has long, dark, braided hair. She's dressed in bone white armor, much more reminiscent of a military tactical assault uniform than a a hero costume. And, most obviously, Toshinori has never seen Izuku look so murderously angry, the way this woman does now, as she pushes back against All for One, sending him stumbling back a few steps in surprise.

'No! Run!' he tries to garble out, but the blood in his lungs just turns his words into weak hacking.

"Easy there, Boy-o. Don't strain yourself with words," a familiar voice orders him.

Toshinori finds his head cradled in someone's lap. Gentle hands run through his hair – hands that appear to be translucent when he can see them out of the corners of his eyes.

'Nana?' he tries again, reflexively, only to get a chastising finger flick to his temple when he chokes again.

"What did I just say, Toshi? Just because I'm dead doesn't mean you can start disobeying me, now that you can hear me again."

Am I dead too, then? He wants to ask.

Nana must read the question in his eyes, because she says, "You're not dead yet. Not even partly. It's the opposite, actually – we're becoming stronger, more like the living. Some of us faster than others," she adds in a mutter, glancing over to where the strange young girl is holding her own against All for One, keeping him at bay and away from Toshinori.

And… that honestly raises more questions than it answers.

"Don't worry, Toshi-boy. Izuku's almost here. He'll get you out, and he can explain everything after you're safe – don't give me that look! It's fine. He knows he can't take on All for One yet, and he's not planning to."

Nana keeps talking, seemingly to distract him from the battle raging next to them.

"Shikako seems to be strong enough to hold him off for now, so Izuku shouldn't have a problem getting you out of here. I'm jealous, honestly. I'm not used to being outclassed, power-wise, but she took to this corporeality thing like a duck to water. Hopefully, though, by the next time we'll all have gotten the hang of this that some of the rest of us can help out too. I'm itching to join in for a bit of pay back."

Nana's not making any sense, and Toshinori's not sure that's entirely the fault of his blood loss.

"Don't worry about it too much right now," she says. "I can see the gears trying to turn in your head, and you're in no shape for that now. You're gonna strain something, thinking that hard, you big lug."

Nana's voice is starting to get further away. Toshinori's vision is blurring, but he still recognizes those streaks of green as Izuku appears at his side.

"Rest, Toshi," Nana soothes as Izuku gathers him in his arms, not so much as glancing as the fight between the girl and All for One escalates behind them. "It will be okay. I promise. Your friends are scarier than he is."

Chapter Text

Shouta Aizawa opens bleary eyes in UA's emergency room, and wishes he hadn't.

It should have been me.

That's the most coherent piece of the turmoil he's feeling, though it's no where close to all of it. Shouta doesn't care to overanalyze the other emotions, however. They're all negative, in their own way, and unimportant, compared to that one.

What else is one supposed to feel, after all, when they're a Hero who has watched their own student, an innocent child, be disintegrated right in front of them?

Gratitude, maybe, that it hadn't been worse. There had been so many villains, and so many untrained kids, and so little help…

Anger, too, at the villains and at All Might and at himself. Would things have been different, if All Might had been closer, or had stayed away from Yuuei to begin with? If Shouta had been faster, smarter, better?

Pity, definitely. For the loss of a bright young girl, and for the pain that will bring to the family she left behind.

There's a warning knock on the door frame, and then Toshinori comes into the medical bay, looking more weighed down than ever before. Shouta's see the man carry whole buildings better than he's carrying this one death.

If they were trying to hurt All Might, Shouta thinks grimly, they got lucky. He would have mourned all of them, but the villains somehow managed to take down one of the two students whose deaths would hurt him the most.

Shouta may find the man annoying, but he doesn't hate him. He doesn't want him to be in pain like this. He doesn't want anyone to be in pain like this.

Toshinori's eyes sweep over the room, alighting on something behind Shouta. He – somehow – manages to slump even further. Shouta turns his head to the other side of the medical bay, and experiences a similar sinking feeling.

Because that's definitely Midoriya's brother Izuku looking banged up as usual, but not distraught, in the bed next to him.

When he notices his mentor's entrance, the boy sinks – embarrassed and guilty and disappointed, but not angry or sad or hurt. Which must mean-

He doesn't know.

Shouta does not want to hear Toshinori break this news.

"Midoriya-kun… there's something I need to tell you."

Izuku eyes begin to water, threatening tears.

"Please. Please don't be too mad at me. I'm sorry that I got hurt again, and that I had to disobey you, but I'm not sorry I stayed to help! It was reckless, but it was the right thing to do! I'm going to be a Hero, and I couldn't just let you and Aizawa-sensei-"

Shouta definitely doesn't feel a renewed surge of pain-guilt-regret at those words. He doesn't. He did everything he could. It just… wasn't enough.

"No! It's… it's not that." Toshinori sighs, placing his hand on his apprentice's shoulder. "It's… yesterday… your sister stayed to fight too. I'm sorry, but she didn't make it."

Izuku shoots straight up in his bed, nearly reinjuring his carefully-splinted limbs with the sudden movement.

"What? Is she okay? Why isn't she here then? Could Recovery Girl not fix her up? Or is she still sleeping the healing off?"

"No, my boy. She's… your sister is dead."

Izuku's eyes unfocus. He looks away from his mentor, to the empty space behind him. His hands fly, as he half mutters, half signs, "No… she wouldn't have left… she'd at least say goodbye before… and you guys are still…"

"I'm sorry," Toshinori repeats, squeezing Izuku's good shoulder. The boy startles, pulled back from whatever thoughts he had gotten lost in.

"She's not dead," Izuku insists with the same certainty Shouta has heard in the voices of countless people in denial over the loss of a loved one.

"Midoriya…" Shouta's voice is kind, but firm. Toshinori is trying to be gentle about this, but he's only dragging things out. It's less painful, in the long run, to get the truth to stick as quickly as possible. "I know it's difficult to accept that she's gone-"

"She's not! Is that why you're so sad? And you too, Aizawa-sensei? Stop moping! Both of you! She's not dead! This is just part of her quirk!"

Midoriya Shikako's quirk is not unlike Shouta's quirk, as far as villain containment and hero support go. She can control shadows, and use them to paralyze people, or make them copy her movement. Nothing to suggest she could possibly survive an agonizing disintegration.

"Sometime Kako overreaches when she's trying to protect people. If she gets hurt to badly, she gets exhausted and she can't hold her solid form. But she'll come back! She always does. It's going to take a little while this time because things were bad… But I know she's still in the shadow, somewhere! She'll be back, once she's rested, or if she's in danger, or maybe even if I'm in danger… But she will be back."

Shouta blinks; Izuku had spoken with the same certain authority that All Might normally uses to assure civilians that things would be fine, and for just a second, Shouta could practically see the older hero superimposed upon his apprentice.

He blinks again, trying to clear his dry eyes, and the image is gone.