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Published:
2025-08-07
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2026-08-05
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36/40
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Trial and Errors

Summary:

“It’s already a fucking miracle you’re not in juvie while being charged with murder—” Izuku flinches “—you can’t afford to slip up.” Mr. Aizawa’s tone is harsh as they slow, his dark eyes resting heavily on him. “Do you understand?”

Izuku nods, whispering a small, “Sorry.”

Mr. Aizawa glares at him, tugging him along, like he doesn’t believe him. “Stop being sorry and just follow the rules.”

Izuku isn’t going to juvie. They said he’s different – doesn’t matter that he’s killed someone, the police is worried about a quirkless child being around other ‘troubled’ kids.

Now this Mr. Aizawa is stuck with him until his trial, and Izuku’s completely, a hundred percent certain that the man absolutely hates him.

Unbeknownst to them, someone is watching from the shadows...

--

Updates every week!

Notes:

I'm back!! A few things I need to address before beginning!

This fic delves a lot into jurisdiction, but since, ONE, English is not my first language, a lot of the terms were confusing so I tried to simplify everything to make it entertaining, NOT fully realistic, and TWO, well, there's just so many Wikipedia articles I can read on the laws for children committing crimes and murder in Japan before I start to lose my mind! That being said, I tried to make everything believable, so I hope it'll still be good.

Now for the characters. Aizawa isn't super aware of Quirkless discrimination. I often see this trope where he knows statistics right off the top of his head, but realistically, his life revolves around quirks (arresting villains, teaching superpowered teens...) so I wanted to make him more oblivious to this issue. I also wanted to make him very flawed, so even though there's the "parental Aizawa" tag, just know it is slow to settle in...

As for Izuku, I'm trying to keep him in character, but he can be a bit of an unreliable narrator, and with the abuse he suffered in this fic, I've decided to make him more defensive. Foster kid Izuku has become one of my favorite trope, but I think I've exhausted every fic with it... So here I go, writing one!!

I will not be beta reading this, I'm too lazy; I usually did it for all my previous fic, but right now I just want to write, so please excuse any mistake.

Also, NEW TAGS MAY BE ADDED LATER!! And with that, I hope you enjoy!

Chapter 1: THE MURDERER

Notes:

“Midoriya, this is Shouta Aizawa.” Tsukauchi introduces them. Izuku stares blankly at them. “He’s going to look after you for the next few weeks.”

(See the end of the chapter for more notes.)

Chapter Text

“I didn’t mean to kill him!” Izuku really shouldn’t be yelling right now. But everything is just pissing him off – the cuffs around his wrists that dig into his skin, the detective in front of him, who keeps giving him pitying looks.

“Midoriya,” the detective, Tsukauchi his name is, says calmly, and he uses the same tone people use with children: patient, kind, pitying. “What you’ve done today is something we take very seriously.”

Izuku falls silent. He feels on fire, with insults bubbling up in his throat, and his hands tremble with rage. He wonders quietly if this is how Kacchan feels like most of the time. But Izuku is not used to this anger – doesn’t know what to do with it. He does well with quiet, and keeping his head down, and saying sorry.

“Not only did you kill someone, but you’ve killed your foster parent and then ran from the cops.”

Not very far, Izuku wants to argue, but he knows when to keep his mouth shut.

They don’t know anything, they don’t know him, they don’t know Izuku. But Izuku knows everything. He knows he killed someone, but it still doesn’t feel real. Or, at least, it hadn’t until the police showed up and brought him here.

The teen swallows. “What’s going to happen to me?” he says, in a small voice, nowhere near as angry as he feels and much more afraid than he wants to be.

The detective sighs, keeping his composure, but Izuku can feel the man’s thinning patience. “We’ve gone over this—Since you’re still a minor, you’ll be assigned a new guardian for the duration of the trial.”

A new guardian, Izuku thinks, clenching his fists. He’s stuck in this loop, and no one ever tries to actually help him – even now, the police is about to just throw him into yet another home.

“I’m only trying to help you,” Izuku scoffs at this, then looks away from the disapproving frown of the detective. “I know you’re angry—”

“I’m not—I-I’m not angry!” Izuku interrupts him, frustration laced in his tone. Then, a sudden wave of anxiety washes over him like cold sweat. “I want to see my mom—why can’t I see her?”

“You know why your mother can’t come at the moment, Midoriya,” Tsukauchi says harshly.

Izuku bites his lips. The detective sighs. A beat of silence passes.

“I want to go home,”

This time, the detective doesn’t answer.

 

 


 

 

A lawyer shows up. They have ten minutes, the man informs Izuku. Then five of those vanish when Izuku refuses to speak. The man assures Izuku that he can tell him anything, that he’s on his side. But this is a hard statement to believe when no one has ever been on his side before.

“If you plead guilty now, you won’t have to go through any trial. They might give you a lighter sentence, too.”

“It was self-defence, I didn’t mean to kill him,” Izuku whispers, finally.

The lawyer purses his lips and gives him a grim look.

That’s all the time they have.

 

 


 

 

Izuku’s a special case. That’s what the detective had said, anyway. And his foster parent before that. Or, dead foster parent, he should say.  

If Izuku had been normal – as in, the normal teenagers that have committed murder, whether intentionally or not – he would have been placed into a juvenile classification home with other kids. But he’s quirkless, and apparently, that makes him too vulnerable around all those violent children.

So, Izuku doesn’t get to go home. Instead, he waits alone in the interrogation room, a cup of hot chocolate growing cold in his hands. It remains untouched. Eventually, detective Tsukauchi comes back, but he’s not alone this time. Izuku wonders if they’ve changed their mind and sending him to jail.

 

“Midoriya, this is Shouta Aizawa.” Tsukauchi introduces them. Izuku stares blankly at them. “He’s going to look after you for the next few weeks.”

This man? Izuku wants to ask. He doesn’t look like he wants to be here, and the look in his eyes tells Izuku the man doesn’t like him very much already. Maybe he’s doing this for money. Maybe if Izuku makes himself small enough, he won’t get on his nerves.

After a long moment of silence, Tsukauchi clears his throat. “Well, it’s getting late. There’s one last thing we need to take care of.”

The detective approaches him with something that looks like a bracelet in his hands, and then crouches down next to Izuku with an unreadable expression.

“You understand that you are basically on house arrest until the end of your trial.” It’s not really a question, but Izuku nods anyway. “This is an electronic tag, it’ll let us know your location at all times. If you remove it, we will know and it will make your situation worse, do you understand?”

Izuku purses his lips.

“Midoriya, do you understand?”

Yes,” he whispers.

“Good,” the detective says, and then he places the device on the boy’s ankle.

It’s worded like a suggestion, but Izuku knows that means his time here is done. He doesn’t know if it’s a good thing, if these few hours at the police station would be the last peaceful ones he’d get in a while, maybe years. He stays silent.

This Mr. Aizawa watches him closely, like he might pull out a knife and stab someone any moment. Like he’s dangerous. Izuku doesn’t want to reassure the man, or prove him wrong, because if he does that, then he’ll have the upper hand, and he’ll realize what Izuku can’t do anything, and can’t protect himself.

The man at the front desk notices Izuku coming, and he probably recognizes him because he turns to grab something before anyone can ask. His tattered yellow backpack drops with a soft thump on the counter, and Izuku rushes to grab it. Dropping to the floor, Izuku makes a quick check that everything is still exactly where it should be.

Notebooks, sweater, water bottle, underwears, check check check

“Where’s my cash?” Izuku’s heart jumps in his chest as he looks up at the officer, genuinely confused.

“Sorry,” the man says, like he means it. “It’s being held as evidence.”

“What?”

The man almost seems amused by Izuku’s reaction, as though he’s trying to keep a smile from forming on his face. “Sorry, that’s just how the system works,”

Izuku opens his mouth to argue further, to yell at him for going through his stuff. But then he tenses as he feels that man’s hand – Mr. Aizawa’s – on his shoulder, and he snaps his mouth shut.

“You’ll get your money back if you get released,” Mr. Aizawa says, sounding very much bored, like he hadn’t just said ‘if’ instead of ‘when’. The man turns to the officer. “Is there anything else missing?”

The officer straightens in his chair, looks down at the file on his desk. “Uh, oh, right,” he turns in his chair and then hands over a Ziplock bag to Izuku. “The chain broke off earlier” he explains.

His All Might keychain. Time has chipped away most of the paint on the figuring, and it barely even looks like All Might anymore. A part of him resents the hero for not saving him, and another, childish part of him feels too attached to really hate him. Izuku takes the keychain without a word.

 

 

The car ride is awkward. Mr. Aizawa had opened the trunk of his car for Izuku to put his bag, but Izuku had made no move to take the bag off his shoulders. Then he’d gotten in the backseat, on the opposite side of Mr. Aizawa, and neither of them tried to make polite conversation.

Izuku holds his backpack tightly in his arms, his fingers digging in the fabric. The air in the car is hot and it makes it impossible to breathe properly, but he doesn’t know if Mr. Aizawa will let him roll down the window, and he doesn’t want to ask. Before the whole incident happened, Izuku had put on multiple layers of clothing to avoid having to carry a second bag, but now that he is confined inside a small, hot place, with his back damp and his hair sticking to his face, he regrets not grabbing a second bag, if he’d known he’d get caught so soon anyway.

But he doesn’t remove his dark green jacket, neither the navy sweater under it, and especially not the two shirts hidden beneath everything, because to do so he would need to let go of his backpack.

The boy stays still, holding onto his bag like his life depends on it – not because it does, but because his bag is his life.

The police already took it away once, what’s to say this Mr. Aizawa won’t want to do the same if Izuku doesn’t listen properly?

 

 

As they enter the apartment, Izuku follows the man quietly, and he thinks the man must definitely be doing this for the money, judging from how bare the place looks. But Izuku still gets his own room, which is nice because he’s had roommates before, and speaking from experience, it usually doesn’t end well for him.

Mr. Aizawa asks him if he’s hungry, and Izuku shakes his head, even though he very much is. He doesn’t want to push his luck when he just got here.

“If you change your mind, just take whatever you’d like in the kitchen,”  Mr. Aizawa says, motioning to where the fridge and cupboard are. They walk to a hallway, and the man gestures to a half-closed door. “There’s my room, wake me if you need anything during the night,”

Eventually, Mr. Aizawa motions him to enter another room. “And that’ll be your bedroom. The space is yours, just don’t damage anything,” he says, waiting in the doorway as Izuku stands awkwardly in the middle of his temporary bedroom. “The bathroom’s just across the hall. If you want to take a shower, the hot water runs out after twenty minutes, so just keep that in mind.”

 

And then Mr. Aizawa leaves to his bedroom, closing the door behind him. Izuku stands there, until the apartment becomes completely silent, and then a couple minutes more, because too much has happened in a single day for his brain to make sense of it all. That, and he doesn’t know if he’s really allowed to do the things Mr. Aizawa has told him he could, like getting food or taking a shower, or if it’s just a test.

 

The thing is, it’s hard to say what Mr. Aizawa will do if he gets angry, because Izuku knows nothing about him. But, he’s been in this system for long enough to know how this usually plays out.

 

There’s always a trick behind every kind gesture: Izuku Midoriya has known this for a long time now.

In every house he’s been in before, it always starts out this way. He’s welcomed inside, gets asked a few questions about himself – empty questions about school and friends, which are both desperate subjects. And then, maybe the host family will keep him for a bit, but it usually turns out one of two ways:

One, he’s too quiet, and they’ll forget about him. They won’t come to pick him up from school on time, and then they’ll forget entirely. Eventually, they’ll forget to bring him there, too. When he was younger, before he knew how to take care of himself, they wouldn’t wash his clothes, wouldn’t buy him products to clean himself, until his classmates would make fun of him and a teacher had to call ‘home’. Small things, little things. Important things.

Nothing he wasn’t used to already.

There’s also the second option, in which case Izuku would be too loud. A child to be dealt with, to be put in his place.

So far, Izuku isn’t so sure Mr. Aizawa is the type of person to forget about a foster, which means it’s more likely it’ll be the second option. On top of that, if the police chose to place Izuku with this man, it must mean he’s used to dealing with children who are ‘out of control’.

And that’s the thing, isn’t it? This time is different, because he’s not just being fostered. He’s being watched, controlled, disciplined, just until they decide whether he should go to prison or not.

He probably will, honestly.

His mom would never forgive him.

Right, he can’t go to jail, Izuku realizes, because then his mom wouldn’t have anyone left to take care of her. He sits on the bed, exhaustion weighing on him, and all of a sudden he forgets how dirty he is, or how he has a new and unpredictable guardian.

Searching through his bag, Izuku finds a near-empty pack of pills. Lucky for him, the police hadn’t confiscated those. With shaky hands, he takes one and swallows it dry, then waits until he falls asleep.

 

 


 

 

Shouta Aizawa is not having a good day.

 

Being a pro hero, Shouta is no stranger to fostering children – especially trouble-makers – but it is the first time that he gets the call on such short notice. They had given him a one hour notice. On his first night off in weeks.

The guest bedroom hadn’t required much preparing: clean sheets were already in the closet, so he had quickly made the bed and gone over his mental checklist to see if he’s forgotten anything. Unfortunately, the unforeseen change in his routine had exhausted him, and he could barely think about anything other than sleep.

To top it all off, Shouta hadn’t been given much information on the kid yet, except that he was a violent boy who urgently needed a home.

 

 

“Violent? Why isn’t he sent to the juvenile center?” Aizawa had asked over the phone.

“The boy is quirkless,” the woman on the other line had said, and Aizawa didn’t understand how this changed anything. “He wouldn’t do well with the other kids.”

“…Right.”

 

 

Most of the time, children will come from a group home to live with him for a while. Some other times, children would travel directly from their last foster family to Shouta’s small apartment, without making a single stop in between.

And, for the first time in Shouta’s life, he picks up a child straight from the police station.

It doesn’t look good. 

 

Shouta is usually skilled in seizing people, especially children, which is one of the thing that makes him good at fostering kids. Keyword here: usually.

The child is quiet. He doesn’t talk, not after arguing with the police officer about money. Which, fair enough. Shouta knows how teenagers can be, wanting independence and all.

But this kid, Midoriya, doesn’t talk to Shouta. And honestly? Shouta is exhausted enough to not mind the silence. With his students’ final exams coming up, he’s been extremely busy, and there couldn’t have been a worse time to take in a foster.

 

 

 

The next morning comes around. Shouta wakes up feeling like he hasn’t gotten a minute of sleep, and goes in the kitchen. Eventually, he knocks on Midoriya’s door to wake him up, and also to make sure he’s still there, but then he remembers the ankle tag, and he realizes that at least he won’t have to worry about the teenager running away.

Shouta has seen violent children before, ones who fight every chance they get. Children who never bark and always bite.

It’s quite hard to believe, looking at the quirkless boy in front of him, that he is anything like those children.

Which is all the more reason for Shouta to be wary of the kid.

“An officer will come by later today to explain how this is going to go,” Shouta explains, taking a sip of coffee. The kid’s eyes snap up to him. He adds, “You could take a shower before then,” which is a polite way of telling him he looks like a mess.

Midoriya stands up from his chair, startled. “Right—”

“I meant after breakfast.”

The teen looks back at his half-eaten butter toast and drops right back into his seat. “Right. Sorry.”

Shouta raises an eyebrow at him, but Midoriya doesn’t say anything else. Honestly, Shouta hadn’t thought he would get an answer at all after last night, but as it turns out, the child does speak. But he looks exhausted, zoning out every chance he gets, so Shouta tries not to bother him if he can help it.

It’s obvious the kid is only being polite to get in Shouta’s good graces. It’s not the first time he sees this: one time, he let his guard down around a foster who had been very well-mannered, even after two weeks. Then a few thousand yens went missing from his wallet, and all four of his tires had been slashed.

The kid finishes his plate. Shouta downs his coffee.

 

 


 

 

Just as Mr. Aizawa had said, a policewoman knocks at the door at 11:30 a.m. sharp. Izuku recognizes her from one of the officers who had chased after him – and ultimately arrested him – just the night before. Maybe that’s how it works – the person who arrests him also has to take care of his case until the trial. Or maybe it’s just a coincidence. Maybe bad luck.

With her, a woman with dark blue hair tied in a low ponytail stands. She’s dressed in a formal gray suit, with a suitcase in her arm. Izuku thinks she looks straight out of a television show, with how serious her face is, and her impeccable her clothes sit.

Daring a glance to Mr. Aizawa, he can tell the man is also somewhat surprised to see a second person there, but he doesn’t comment on it. Instead, he steps to the side and lets two more strangers inside his house, even though he looks like the type of person to never have any guests over.

 

“Your trial is in a week,” the policewoman states, scanning over the information in her thin file. They’re sitting in the living room, with Izuku on a chair and the two woman facing him on the couch. His temporary guardian watches from a chair a bit further away. “Since you’re a minor, you’ll be provided with a lawyer to defend you, but you already know this, since you’ve already met him.”

“When will I see him again?”

“If everything goes well, you’ll see your lawyer at the trial.”

“But then—how will I—?”

“I would ask you to be quiet until we finish talking, Midoriya.” She gives him a stern look before continuing. “Now, the trial might take a few days, but Mr. Aizawa will be there to accompany you during the whole process.”

The woman licks her finger to make the turning of pages easier as she flips through the file, making the boy cringe.

“Until then, Ms. Naito will take you through a mental evaluation,” She gestures to the other woman next to her.

“I don’t think I need it, though,”

“I’m afraid it’s mandatory,” the psychiatrist next to her, Ms. Naito, says.

Then, the policewoman turns to Mr. Aizawa, a professional smile forming on her lips. “Mr. Aizawa, I know this was all very last minute, so we’re very grateful you’re taking the time to deal with Midoriya for a bit.”

“Right,” he says, scratching his chin. “So, I’m guessing that means I won’t be going back to work until the trial is over,” he adds.

“Unfortunately,” the officer confirms.

Right.”

Mr. Aizawa seems to hesitate, but at the end of the day, neither he nor Izuku really have a say in any of this. The man is just there to give him a place to sleep until they ship him off to jail, just to delay the inevitable like some cruel joke.

Eventually, he agrees to watch Izuku, and the adults shake hands politely, talk of which times would be best for the evaluations and all the paperwork that comes with it. Then they leave, and Mr. Aizawa goes back to his small laptop while Izuku stares at the wall.

 

Izuku wishes he could see his mom. Maybe she’d know what to do.

 

 


 

 

It’s laundry day in Mr. Aizawa’s apartment. Izuku hadn’t thought some people reserved specific days to do laundry before. But his new guardian is different, and he doesn’t like Izuku, so the teen tries to be quiet when the man asks for any clothes he might need to wash.

Izuku knows how to do his own laundry, but Mr. Aizawa doesn’t offer to let him do it, so he guesses he must not be allowed, for some reason.

His small pile of wrinkled shirts and sweaters fit comfortably within his arms, and although Izuku doesn’t particularly like staying in his T-shirt, all his sweaters are starting to smell bad, so he’d rather get this over with.

Mr. Aizawa watches him with an unreadable look in his eyes, and then looks at the pile of clothes. His sweaters mix with Mr. Aizawa’s.

“Usually, you need to dress a bit fancy to go to court,” Mr. Aizawa tells him calmly, closing the door of the washing machine. “I could ask Tsukauchi if someone could go grab you some more clothes from your previous house, if you want,”

Izuku opens his mouth, then closes it. He doesn’t know what this means. Why is Mr. Aizawa trying to give him advice? Is he being nice? Why? Maybe it’s because he doesn’t want to be seen with a child wearing cheap clothes at court, or something. Izuku understands why this could be embarrassing.

“I, um,” Izuku bites his lip, not knowing how to turn down Aizawa’s offer. They hate it when he stutters. He forces his eyes to look at his guardian. “I don’t have anything else.”

Mr. Aizawa just stares at him. “Nothing?”

“Uh—No, sorry.”

“You don’t have to say sorry.”

Izuku barely manages to stop himself from saying ‘sorry’ again. Then, Mr. Aizawa sighs and rubs his eyes, and Izuku tenses, waiting to get yelled at or something.

“I’ll ask around, maybe I can convince the school to let you borrow a uniform just until the trial ends.”

“Oh um, that would be nice,” Izuku feels surprised at the lack of mocking remark. He’d thought the man was annoyed, but maybe this is Izuku’s chance to make Mr. Aizawa hate him a little bit less. “I was wondering… You said your job was important, earlier.”

“I’m a teacher,” Aizawa says, yawning.

“Oh.”

Izuku doesn’t like teachers that much, and teachers always hate him. It feels like a bad idea, now, to be trying to get to know his guardian now. Izuku doesn’t believe in magic or anything, but there’s still a part of him that think he’s cursed somehow, in a way that makes every one of his teachers hate him.

But Mr. Aizawa isn’t his teacher, so he lies to himself that it probably doesn’t count.  

The teenager swallows, following the man as he heads back to the living room. Izuku pushes back the feeling that he’s bothering the man, because if Mr. Aizawa is being nice to him, by going as far as borrowing a school uniform to make him look more put-together at his trial (or to avoid embarrassment), then he’s probably expecting Izuku to, well… Expecting something from Izuku, to make up for having to babysit him.

“What, uh, what do you teach?”

“Homeroom.”

“I—I like homeroom.” Izuku lies.

Mr. Aizawa hums in response, sitting down at the counter and opening his laptop sitting there. The charging cord is plugged next to the coffee machine, but it’s not very long, so it hangs in the air and blocks half the kitchen.

Clearly, Mr. Aizawa doesn’t feel like talking, and Izuku’s conversation skills are about as good as that of a three year old.

“I need to work for a bit, but you can watch TV, just don’t put the volume too high.”

Izuku nods, but Mr. Aizawa isn’t looking at him, so a moment later he whispers a quick “Okay.” He recognizes a dismissal when he hears one.

 

 

 

The news are playing. Izuku calls them hero news in his head, because that’s pretty much all it ever is.

He’s only half listening, though, waiting for the weather report to end so they can get back to the segment about Mt. Lady’s latest fight. He works on her sketch, adding some shadows until he can get another good look at her costume.

But instead of Mt. Lady, it’s All Might they show on TV – he’d arrested a villain the night before, not even a particularly dangerous one at that. Just some petty criminal who happened to be at the wrong place at the wrong time.

They show a clip of said criminal being handcuffed and dragged into a police car while All Might gives a quick word to the reporter.

It dawns on him, for the first time since everything happened, that Izuku’s a criminal. If All Might had been there that night, if he’d been the one to find Izuku, he wouldn’t have saved him – he would have arrested him.

I can’t be a hero, Izuku thinks, heart jumping in his chest. I’m a criminal, I’m a—

Mr. Aizawa is behind him, watching the news, or watching Izuku watch them. When did he get here? Izuku follows his gaze and realizes the man is looking at his notes. Izuku gasps and shuts his notebook close, blood rushing to his face. This is stupid, he knows what the man will say, that Izuku is a silly stupid child who—

“Do you like heroes?” Mr. Aizawa asks.

Izuku turns back to look at the television and frowns. They’re talking about a hero that died recently.

 

“No.”

 

 

 

Notes:

I've been working on this for a while, so I hope you enjoyed this chapter! I have a few more pre-written but I'm keeping the updates relatively slow, in case I need to edit some parts. But if you ask nicely, I might post next chapter sooner ;)

If you've enjoyed this, I have a few recommendations for you!

Do Your Best by Gotambeat, which inspired me to write this! Aizawa is Izuku's "last chance" with foster homes, but there's some dark stuff going on. Ft. parental All Might!

Together Lost by the same author, which is a different take on "Do Your Best" and magnificiently written! (unfinished).

When Realities Collide by LowlyWriter, not a foster Izuku fic, but he does get arrested and it's absolutely thrilling, with a gut-wrenching plot-twist.

I’ll Be Your Hero (At The Cost Of Everything) by Finally_Free and little_clown, just an (unfinished) masterpiece, Izuku is kidnapped by Chisaki and and forced to do morally-grey actions. Eventual Dadzawa!

 

Thanks for reading! Don't hesitate to leave a comment, they are food for my soul <3