Chapter Text
Night patrols were such a pleasant change of pace. No fans, no cameras, no obligations between Izuku and the job. Peaceful, for a certain definition of the word.
And it wasn't that Izuku disliked those things! But being the number one hero meant that a daytime patrol was more of a PR event than anything else—signing autographs and posing for selfies. He knew that taking up All Might's mantle was a good thing, but sometimes he missed being nobody. Peace was in short supply, these days.
It must say something about him, that his idea of a vacation was doing his job at night, just to avoid attracting a group of excitable onlookers.
The crime was also quieter at night. The villains looking to make a statement were much more prone to showboating during the day. An audience was part of the plan. The night, though? That was for the mundane. Muggings and convenience store robberies. Kacchan would scoff that it was a waste of his talent, but Izuku enjoyed helping in ways that didn't make headlines. It might not be saving the country, but there was value in helping people one on one, in making sure a tired clerk got home safe. Sometimes being number one didn't feel quite real, and being out here, doing small good? It was grounding.
So Izuku spent a couple nights a week haunting the rooftops, and the rest of the country didn't have to worry about their top hero cracking like an egg and running off to become a mountain hermit. Everybody won.
The night had been quiet so far. Izuku had spent most of it drifting from rooftop to rooftop, listening to the quiet sounds of a sleeping city. And giving one starstruck hot dog vendor a heart attack by dropping in as he set up to catch the drunks after last call.
Quiet nights rarely lasted, and so Izuku was not surprised when he caught the iron scent of blood. A lot of it.
Izuku chased the scent to a nearby alley, peering over the lip of the rooftop and into the gloom below. He could make out two figures, one of them unmoving on the ground. Izuku didn't hesitate. That much blood meant the victim was either dead or dying, and he had no time to waste.
Activating his quirk, Izuku leapt from the rooftop to the alley below, cutting off the attacker's escape. They were crouched over the body, back to Izuku. "You're under arrest for—" his gaze cut to the victim, gut twisting. Goddammit. "Murder. I suggest you come quietly." Izuku always tried, but he found they rarely listened.
The killer wiped his blade clean against the dead man's sleeve, unhurried and unconcerned. Rising to his feet, his hair began to float and his eyes gleamed red as he turned, Izuku's quirk flashing out like a blown bulb. He sucked in a sharp breath of recognition.
Eraserhead. This was the first time Izuku had encountered him, but he knew of him—of course he did. A hero turned killer, a traitor, a puzzle. Nobody seemed to understand why he had gone bad, but everyone agreed that he was dangerous. He'd killed heroes before, and his quirk was a terrible equalizer. Izuku should attack, hit first, try and use the element of surprise to his advantage. "You're Eraserhead," he said instead, like an idiot, the little fanboy in his soul missing the memo that the once-great underground hero had fallen far indeed.
The inane statement earned him a smirk. "And you're Deku. Guess that makes us both famous." The smile fell away. "I'm not interested in killing you. You should go."
The statement sent Izuku's thoughts spinning. Not interested in killing him? Why? Was he trying to avoid a fight he wasn't sure he could win, or did that mean he had criteria ? Everything Izuku had heard about the man seemed to suggest that he killed without rhyme or reason, but was that really the case?
"Why not?" he asked.
Eraserhead cocked his head, and Izuku was pretty sure the question had thrown him. "Have you done anything to deserve it?"
Deserve it? He was asking if Izuku had done anything to warrant killing him over? God, he had so many questions. "No?"
"Then go."
Izuku looked at the body, then back to Eraserhead. "You know I can't do that."
For a brief moment, Eraserhead looked incredibly tired. "I figured." Then his scarf shot out and caught Izuku's wrist, and he was too occupied with defense to worry about anything else.
Eraserhead was fast and Izuku couldn't remember the last time he'd had to fight without his quirk. A flash of metal, and Izuku twisted out of the way as Eraserhead came at him with the blade, tugging uselessly against his bound wrist. Sight line. His quirk required a sight line, if Izuku could break it, blind him, even for a moment, it would be enough.
He never got the chance. Eraserhead kept pressing him, assault relentless and vicious, and it was all Izuku could do to keep clear of the blade. He couldn't let the man keep him on the defensive forever, or he was going to lose. Izuku caught the length of scarf in one hand, tugging sharply in a bid to pull Eraserhead off balance, dropping low to try and take out his legs.
It didn't work. Eraserhead dodged the strike easily, and Izuku realized he'd left himself open the instant sharp steel bit into his shoulder, driving him to the ground with the force of the blow. It hurt, but Izuku was no stranger to pain—the worst of it dulled by adrenaline. Eraserhead seemed surprised by Izuku's struggles. He twisted the blade, and by the time the white flash of agony receded, Izuku was well and truly pinned.
Eraserhead stared down at him, expressionless. "You should have left when I told you to."
"Wouldn't be much of a hero if I ran away," Izuku gasped, thoughtless, trying to keep him talking while he tried to find a way out of his predicament. This close Eraserhead's scent revealed that he was an omega, which was surprising, but potentially useful information. It meant that he shouldn't waste his time with a nut shot. It also meant that even without his quirk Izuku was the stronger of the two, so if he could just get some leverage , maybe—
With a miniscule shift of his weight, Eraserhead killed that plan. Despite his situation, Izuku couldn't help but be impressed. Eraserhead was better than rumor had implied. Izuku just wished he wasn't going to have to die for the privilege of a fight.
"That sorry sack of meat wasn't worth this, hate to break it to you." Eraserhead's words were easy, conversational, like he wasn't discussing the man he'd just murdered.
A wave of dizziness struck Izuku, and he blinked against the sensation. It was too soon to be blood loss, and too rapid. "What?" he asked, tongue thick around the word as his vision went black at the edges.
Eraserhead's quirk faded, and Izuku struggled for his own against the black tide threatening to pull him under, but he couldn't quite seem to reach it. "Poisoned blade," Eraserhead explained. "Handy tool." His weight vanished as he stood, but Izuku's connection to his body seemed distant, movement beyond him. "Next time, do us both a favor and listen. "
He stepped away, the sound of his voice becoming hazy and indistinct as Izuku was swept away.
* * *
Izuku startled awake in a hospital bed, which was a surprising turn of events after the night he'd had.
"Fucking finally, " a familiar voice said, and Izuku blinked over to find Kacchan sitting in the chair near his bed, wearing his pajamas and an annoyed expression.
Izuku was confused on several counts. Not the least of which was the fact that he was still breathing. Easy questions first, though. "Kacchan? What are you doing here?"
They'd wound up working together more by circumstance than intent, but after a rough first few months it had been... surprisingly good. From coworkers to partners to friends, and Izuku was glad he'd given it a chance. Kacchan had done a lot of work on himself, on becoming a better hero and a better person. Izuku was proud of him.
He was still a huge jerk, though.
His partner looked unimpressed and for one woozy moment Izuku worried that Kacchan could read his mind.. "I'm your emergency contact because you didn't want to worry Auntie Inko, remember?"
Oh. Right. It had been so long since something had taken him down that he'd forgotten. He pushed himself upright, grimacing at the pain in his shoulder. "What happened?" he asked. Everything felt a little hazy. He'd fought Eraserhead, he remembered with a quiet thrill, and then.. what?
"I was hoping you could tell me, asshole." Kacchan crossed his arms, brusque demeanor not quite masking worry. "All I know is they called me at three in the fucking morning to tell me you'd been found bleeding out in an alley next to a dead body."
Izuku frowned as his recollection cleared. "What about the poison?" he asked, touching his shoulder. Had they found him quickly enough to counteract it?
Kacchan looked at him like he was crazy. "You weren't poisoned . They found a strong sedative in your blood, but that was it. Stop jumping around and tell me what fucking happened."
A sedative? What? Izuku shook his head, trying to clear the fuzziness clinging to the inside of his skull. "I came across Eraserhead after he'd killed the man in the alley. We fought." Izuku grimaced. "I lost."
Kacchan whistled. "Shit, then maybe you are lucky to be alive. Bastard has a casualty list a mile long, and you wouldn't be the first hero on it. So what happened?"
Eraserhead had let him live, was what happened. His blade hadn't been coated in poison, but in some sort of sedative. Playing the fight back in his mind, Izuku realized that every strike had been deliberately non-lethal. I have no interest in killing you. "He let me live," Izuku said, chewing on the realization. "After he knocked me out it would have been easy to kill me, but he didn't."
A vague memory tugged at him. "How did they find me?" he asked. It was an isolated alley in the middle of the night. Izuku should have bled out long before a passerby stumbled across him.
"Someone called it in," Bakugou said, resting his elbows on his knees and leaning forward. "And what the fuck do you mean, he let you live? You saying the psycho killer went 'nah, already filled my quota' or something?"
"He's not a psycho," Izuku muttered, which wasn't the point but the label bothered him. Eraserhead had seemed entirely sane, which was much more dangerous. "Who called it in?"
"Do I look like a cop? I don't know. Why does it matter?"
Izuku squinted against the hazy memory. Eraserhead had been speaking as he passed out, most of it a senseless mumble in his head but one thing stood out: hero down . "Eraserhead called it in," he realized. He let him live, and he'd made sure that Izuku would be found before he bled to death.
Bakugou frowned. "Why would he do that?"
I'm not interested in killing you. The words echoed around the walls of Izuku's mind. His experience did not mesh with what he had been told, and Izuku could feel curiosity catch like a fish hook.
"I don't know, but I'm going to find out."
* * *
Kacchan had been understandably unimpressed by Izuku's sudden fascination with a villain whose only motivation appeared to be murder, but he also knew a lost cause when he saw one. So when he dropped a fat file on Izuku's desk labeled Aizawa, Shouta (Eraserhead), Izuku recognized it for what it was—a bid to help him satisfy his curiosity without getting stabbed again. It was kinda sweet.
"Jackpot, nerd," he said, looking smug.
Izuku stared, because it was more than the police reports, it was the entire hero commission file. The sort of thing they should technically have access to, if access meant running around in bureaucratic circles until you folded under the withering stare of a secretary. "How did you get this?" he asked, smoothing a hand over the cover like it was something precious. He knew Kacchan didn't understand his weird tangential obsessions, but that didn't mean he wasn't willing to help out, sometimes.
"I'm fucking amazing, that's how." He jabbed a finger at the file. "That doesn't leave your office or I will burn you bald, understood? They're neurotic about this guy."
"I'm not surprised," Izuku said, flipping open the cover and scanning the first page in mounting excitement. "There have been dirty heroes before, and even a few that went full villain, but to this extent? This sort of violence? He's the first. Or at least the first I've ever heard of." There was a puzzle waiting to be solved in these pages. Why he'd let Izuku go, and maybe what drove a hero to this sort of darkness to begin with.
"I can't believe your fanboy bullshit extends to villains now," Kacchan said, brows furrowed. "If you weren't such a sparkly-ass loser, I might be worried."
Which meant he was worried. "He was like us once, Kacchan. I know you never paid much attention to the underground scene, but I did, and he was a good hero. What changed? Why did he let me live? I just... need to figure it out."
A soft snort. "Well, if anyone can figure that out from a pile of reports, it'd probably be you. Just don't go too deep down the rabbit hole, alright? Whatever his reasons, the man made his choice. It's our job to bring him in, not understand him."
"Ah, but one must first understand an enemy in order to defeat them!"
Kacchan rolled his eyes, and leaned over Izuku's desk to punch him in the shoulder—the good one. "Can the wise mentor bullshit. I've thrown plenty of lowlifes in prison without understanding them, and it's better for my sanity that way." The look he cut Izuku was pointed, and a little concerned.
Izuku knew Kacchan thought his empathy was going to get him in trouble, someday, and maybe he wasn't wrong. But Izuku liked to think it made him a better hero at the end of the day. "I'll be fine, Kacchan."
"Like you were ever fine to begin with," he muttered. "Whatever, I've got shit to do, enjoy your nerdery and don't get stabbed again." He stomped out of Izuku's office before Izuku could point out that his encounter with Eraserhead had been a fluke that was unlikely to be repeated.
Which left him alone with Eraserhead's massive file. Izuku called his assistant to clear his schedule, pulled out a fresh notebook, and got to it.
It started with the basics. Name, age, blood type, quirk, gender. Izuku's attention snagged on the last. He'd noticed that Eraserhead was an omega during their fight, and that was a curious detail. Omegas weren't, as a general rule, prone to violence. They could be downright vicious when threatened, or in the defense of children, but these were both reactive traits. Omegas were protective by nature, not aggressive. And sure, that was a very stereotypical understanding of behavior informed by instinct, but the rule generally proved true. Even omega heroes tended to be drawn to the profession by the opportunity to protect.
So it was likely that Eraserhead—Aizawa rather, Izuku doubted he used his old hero name anymore—was operating counter to his nature. His years as a hero and a teacher both supported this hypothesis. Izuku had never heard whisper of anything that might point to a violent nature all along—issues with excessive violence and the like, or captives dying under his care. Something in his gut told him the reports would corroborate that.
People didn't turn to murder for no reason. An omega wouldn't turn to murder for no reason. The narrative they'd been given, the 'guess he just snapped' justification, didn't hold up to examination. Nothing about his encounter with Aizawa suggested that the man had lost his mind. He'd given Izuku more than one chance to leave. He'd incapacitated him without killing him. He'd ensured that Izuku would receive medical care. None of these actions were those of a madman, or a senseless killer.
A brief, clinical bio followed. Both parents deceased. A UA student, then an underground hero, then a heroics instructor at UA. No previous history of violence, although he had displayed an occasional disregard for authority. Nothing useful in the bio itself, but the photo clipped to the corner? Oh, that was something, all right.
It was Aizawa as a teenager, with two other boys. One he didn't recognize, but the other, the one with an arm slung over Aizawa's shoulders? His old English teacher, Present Mic.
If Yamada-sensei was friends with Aizawa, he'd have to have some sort of insight. Even if he didn't know what caused the man to go rogue, he'd be able to tell Izuku about who he used to be. That was something. Although, they had to have interviewed him after what happened, so where? Izuku went rifling through the pages until he found what he was looking for: an interview transcript.
Izuku could feel Yamada-sensei's frustration coming off the page in the short, clipped answers. No, he didn't know why Shouta had murdered a hero. No, he didn't know where he was now. No, he'd had no idea what he was planning.
A hero? Aizawa's first kill was a hero? Izuku flipped through the reports until he found the one he was looking for, seven years old. Shatter. Izuku remembered him, an older hero with the ability to control glass. A more versatile quirk than it sounded like, and it had made him a force of nature in urban combat. Izuku remembered hearing that he'd died, but he'd had no idea that Shatter was Aizawa's first victim.
The report was concise and clinical. No sign of forced entry. No defensive wounds. No sign he'd used his quirk at all. Killed by a single stab wound to the heart.
Izuku sighed, heart aching. No defensive wounds because Aizawa was a colleague, a fellow hero. Shatter would have had no reason to suspect his intentions. It was sad, and once again Izuku wondered why. Have you done anything to deserve it? Aizawa's voice drifted across his memory, and Izuku stared down at the report, unseeing. Was that it, then? Had Shatter done something Aizawa believed he deserved to die for?
It wasn't an answer he'd find in a police report. Instead, Izuku did a little digging into the records database. Shatter had been involved in a major altercation a few weeks before his death, a battle with a villain that got out of hand. Property damage, a few wounded civilians but nothing serious and... Izuku sucked in a sharp breath. One death. A hero student, interning with Shatter's agency. Kimiko Mizaki. Cause of death: blood loss due to multiple laceration wounds.
Shatter's quirk, it had to be. The villain he'd been fighting had a strength quirk, nothing that would cause that sort of injury, but Shatter? He could turn every window in a city block into a mass of glass daggers. The student must have been caught in the crossfire.
Izuku sat back, rubbing his eyes and heartsick at the thought. Fights could be chaotic, and friendly fire was always a risk, but to lose a student to your own quirk? Izuku couldn't even imagine.
A quick search confirmed what Izuku suspected—Kimiko Mizaki had been a second year at U.A., and one of Aizawa's students. Was that what it was, then? Vengeance? That didn't seem quite right. It was a tragic accident, but an accident all the same. There had to be something Izuku was missing.
A deeper dive into the records database turned up a video statement from Shatter on the incident that turned Izuku's blood to ice.
The video begins with Shatter, sitting at a table and looking annoyed. "Is this really necessary?"
A voice from behind the camera replies, "It's standard procedure." Shatter sighs but does not argue, and after a moment the interviewer asks, "Can you please describe for us the events that led to Ms. Mizaki's death?"
"The girl got between me and the villain, there's not much to tell." Shatter does not sound upset. He sounds bored.
"Did you know she was there?"
"Yes."
"And you chose to attack anyway?"
Shatter rolled his eyes. "Yes. The choice came down to one bumbling student or protecting the people from a rampaging villain. It's a shame she died, but that's the risk you take when you want to be a hero. You learn how to hack it, or you die."
The video ended, and Izuku stared blankly at the screen. Despite Kacchan's opinion to the contrary, Izuku wasn't naive. He knew that being a hero didn't make someone a good person, that there were people in the profession for fame and money. But to hear someone so callously treat a child like, like an acceptable casualty? It was appalling. Surely that sort of thing wouldn't be tolerated? But try as he might, Izuku could find no evidence that Shatter had faced any sort of penalty for his actions whatsoever.
Even if he'd genuinely believed the girl would have lived, it was manslaughter at best. Heroes should not be above the law.
And yet, nothing.
Izuku wondered if Aizawa had seen the same video. Imagined what it must be like, to lose a child under your care, only to discover that the person responsible faced no consequences. To learn they didn't even care. It was disturbingly easy to see how Aizawa might have made the decision he had. To be a hero and know that your blade was the only way a dead child might see justice.
Justice. The concept settled heavy beneath his ribs. Could that be it? Could justice be what this was all about?
Only one way to be sure.
Izuku spent the next several hours pouring over report after report, cataloging each victim, and the pattern that began to emerge was telling. Some of them were easy—slippery villains greasing the right palms to evade capture. Others were harder. A corrupt politician with a predilection for children, hero commission officials lining their pockets with blood money, shitty heroes masking their crimes behind a veneer of respectability.
More fascinating still were the rescues. Witness reports of Aizawa swooping in like some sort of avenging angel, saving children, victims, and in one amusing case, protecting a clueless secretary from a yakuza firefight. In all the reports, there was no evidence of the man hurting innocents. No collateral damage. All the evidence pointed towards him going out of his way to protect those who needed it. Several reports suggested he'd been injured doing so.
The common thread through all his kills was that people had been hurt, and nobody had paid the price. In most cases through the failure of the system or blatant corruption, but they all—to borrow Aizawa's phrasing—deserved it. The former hero might be classified as a villain for his actions, but that wasn't quite true, was it? He was seeking justice for the people the system had failed. He didn't hurt people that did not fit within his framework, even when it was inconvenient.
His methods might be bloody, but it was starting to look like Aizawa was not quite the villain everyone claimed him to be. Izuku chewed his thumbnail absently, staring down at his notebook. His answers had only led him to more questions, and the hook dug deeper.