Aizawa asks, "How did this happen?"

After a long, long moment, Yagi tells him. And then he says, "Shouta, this isn't your fault."

Yagi is wrong. .

Five young heroes have been taken out in a single strike. Aizawa demands to see the video footage, and everyone knows him well enough not to say no.

The security video shows the end unexpected team- up, the result of a large-scale pursuit after a heist which led through different quarters of the city. The situation climaxes at the docks. Five heroes converging towards one point — Froppy, Cellophane, Creati, Chargebolt, Ingenium.

Their teamwork is flawless. They communicate while barely speaking. The fight is clearly in their favor. They are coordinating towards a final strike.

And then all five of them just. Stop.

They don't freeze in any unnatural way, not as if they were hit with a paralytic or mind control Quirk. They don't go unnaturally blank-eyed and loose the way people do under Shinsou's control. Aizawa watches them all make the split-second, conscious choice to grind themselves to a halt.

There is a long moment where they all look — oddly lost. Young and confused. They resemble themselves in the first few weeks of his class, young and untrained and hungry for guidance. They are looking around for — for the source of the noise.

Because what stops them is a noise.

And in those few moments of confusion, of pause, of

stillness, the trap springs shut. And it is brutal.

Aizawa grits his teeth, pauses it. Glares over at the beat cop in the room with him.

"You have a version of this with sound." He does not ask this; he states it.

"Uh," fumbles the cop, "yes, but, the Detective—"

"I don't care what the detective said. Show it to me." The beat cop never stood a chance.

The new video is from a different angle. He can hear the sounds of the battle now, the quick calls of his former students to each other.

The fight progresses the same as it did in the first video. Except, this time, Aizawa hears the sounds which caused all five of them to freeze so easily.

He turns the chair away from the screen. He places his head on his knees, and shuts his eyes.

Behind him, he can hear the video continuing. Once again, sounds being put to things he's already sat through. Dull snaps of breaking bones — Froppy's arm being cracked, once and then again, something hard against Creati's skull — desperate calls for friends and comrades, the slick, sickening sounds of injury — a blade up through Cellophane's torso, blow after blow to Ingenium's face and neck. Sharp gaps of pain, as Chargebolt is crushed.

Aizawa gets up and walks out of the room.

On the screen, the sounds change, as pro-heroes Deku and Dynamight descend onto the battlefield like a pair of young, vengeful gods. Dynamight screaming with a protective rage not heard since they were all fighting Shigaraki, twisting into a Howitzer so bright it hurts to look at as he forces the villain away from Chargebolt. Deku, not as loud, moving to get every friend to safety to counter the inferno-level offensive his partner is waging.

Aizawa doesn't hear any of it. Doesn't hear the question that tears itself from Ingenium's throat, right before the video ends: 'Is Sensei here?'

.

The reason this has never been a problem before is, most likely, because there's never quite been a class like them before. Not one that saw so much action together when they were still young. Still learning .

Wires get crossed. People have reactions nobody could have predicted. That's what everyone keeps telling him.

But Aizawa should have predicted it. Because it isn't like he's never noticed the way this class responds to him. It isn't like he hasn't taken advantage of it before, though only ever for their own good. It had been useful, back when they were children forced into combat. It had been useful afterwards, when they were children who had been forced into combat, and needed to be talked down from panic attacks and flashbacks and spiraling thoughts.

Aizawa has known about this. Aizawa has never fixed it. And Aizawa is nothing but brutally honest, especially with himself, and therefore knows that he never fixed it because it was, on some level, a relief to have it. A comfort. It has never occurred to him that it could be weaponized, which is foolish and naïve to the point of hilarity.

And now an entire generation of top heroes has been trained — no, more than that, they have been conditioned — to respond to, and obey unconditionally, one voice. Over the course of their notably traumatic time in training, they have all learned, deeply and completely, that when that voice gives your orders in the field, you follow them or you die. That voice cares about you. That voice's deepest motivation is for you to get out of this alive.

Unless it isn't Aizawa using it. .

"Stop, all of you! Not another step , stay right where you are."

.

There are currently, in Japan, around a million people with some kind of vocal modulation Quirk. A fraction of those could be called vocal mimic Quirks.

One of them just became infinitely more dangerous.

.

None of the five who were ambushed are conscious. Both Sero and Asui are in intensive surgery, Sero to repair organs and Asui to repair bone. Yaoyorozu has been put in a medically-induced coma until the swelling in her brain goes down. Iida is the least injured out of all of them, and is sleeping off a severely bruised trachea.

Kaminari, currently, is on a ventilator.

The rest of his old class clings to each other in a waiting room. Aizawa cannot make himself join them. He knows what all of them look like when they fall through their stages of grief, and doesn't want to look at it again, so he tells himself.

"You used to give Midoriya detention for this level of self-flagellation, Eraserhead."

Aizawa turns slowly to look at the person speaking. Detective Tsukauchi is too old for this bullshit, and says at the start of every January that it's the year that he'll retire. He has yet to make good on that promise.

"Did you catch them?" he asks, and ignores how wrecked his voice sounds. "The one who did it."

The detective says, "We did not," and Aizawa closes his eyes.

"How am I supposed to train it out of them, Tsukauchi? A reaction that immediate, a reflex that deeply embedded? Get them all to stand there while I shout abuse at them, until that's all the think about when they hear my voice?"

Tsukauchi looks horrified. "Aizawa, what—"

"I feel like I've brainwashed them," he says over a dry tongue. "I feel like I've—"

Tsukauchi interrupts him, a strange tone in his voice. "Aizawa. You don't think you failed by taking care of them too well, do you?"

Aizawa doesn't say anything. Can't say anything.

Because the truthful answer to that statement is yes. Tonight, that's exactly how he failed.

And, so long as his voice is comfort and a villain can speak in his voice, he will continue to do so.