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English
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Published:
2026-02-25
Updated:
2026-06-25
Words:
56,252
Chapters:
16/50
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Musutafu is a lovely city (And alternative Yokohama is okay I guess)

Summary:

What would happen if Chuuya and Dazai were sent on a mission that went horribly wrong?

Which ends up sending them to an alternate universe where superpowers are too common and crazy people in spandex run rampant through the streets.

Even worse!

what happens when in this place, the people that the pair of Mafiosos have lost (and have not lost) are living and will do everything they can to help what they perceive to be two unfortunate teens?

OR

Throw two grieving guys into a box (The My Hero Academia Universe). Shake it very hard (De-age them) and make them casually meet the alternative alive and happy versions of their loved ones. (And not so loved ones)

For the love of the game.

Oh and they go to UA eventually I guess.

Notes:

English is like my third language, which I learned by watching movies with subtitles and reading fanfiction, so you'll have to bear with me.
I pulled this 13-page thing out of my ass and I have no idea what I'm doing. I haven't written a full series of fan fiction since I was an Amino user at the age of 10 and every oneshot of mine is orphanaged.

Anyways.

Mori is an okay man in this and is not a creep (Alternative "Mori" is the problem)

 

Another thing is that I'm going to ridiculously increase Dazai's power to be kind of a shield sometimes because I can.
That's what the labs are for.
Chuuya is already op so not much change to him.

Let me glaze.
Uh...
Warnings:
Human experimentation, grief, bad hygiene and shaming to it, misery? Implied abuse from Oda's perspective probably, also injuries I guess

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

Chapter 1: Dazai's Ability Will Keep Both Of You Safe— Said the fuck you guy.

Summary:

I might rewrite this because I kinda don't like it but bare with me.

This was my first publicly published chapter 💔

Notes:

(See the end of the chapter for notes.)

Chapter Text

Yokohama is a lovely city.

Even when it’s been submerged in rain and clouds for a the last two days or so.

Dazai might envy the ability to let drops fall from his eyes the way those nasty clouds have been doing lately.

It's almost as if the weather decided to hold that over his head ever since the last golden hour he had the misfortune of witnessing.

Maybe the rain isn’t that bad.

Maybe Odasaku once wrote about the weather. It’s a cliché writing resource, after all.

Dazai would take a poem about raindrops over nothing.

Because nothing is what he has now.

Odasaku is nothing.

Nothing but a corpse six feet underground.

 


Morning has just begun, and according to Mori, there’s a very important situation to address. The brunette has no plans to entertain the doctor for more than a week. He just needs to find the right moment to give Chibi’s new car a proper goodbye before leaving the Port Mafia. It would be a shame if that wheeled abomination somehow could be fixed.

Still.

He is leaving.

So he can save some orphans and all that.

But of course, the day already sucks.

When he fully opens his eyes and drags his pathetic excuse for a human body off the cold floor of his beautiful, completely not cold, and very empty home, he’s greeted by a dull ache.

It’s not dramatic pain. It’s just there. The only dramatic thing would be the strange mix of what could be emotions inside him.

Or just nothing at all.

Emotions are little wires. Touch the wrong one and you blow up. That’s why he doesn’t touch those things. It’s not his business. He’s not even human to begin with so he shouldn´t really bother.

Unfortunely for him and for anyone that has to deal with him...

 

Even the inhuman can have a job.

 

And his ringing phone — which he won’t answer — reminds him of that fact.

.

Once he’s done whining and finally upright, he walks out of the container with heavy limbs, not even bothering to clean the dried blood and grime off himself before heading toward the Doctor’s office.

What is the man going to do? Throw antiseptic at him?

Ah, it doesn’t matter.


 

The Port Mafia headquarters are long.

Long and clean. The kind of place where even the air feels fancy. That’s how Chuuya knew something was wrong before he even spotted that idiot behind him.

He could smell him.

That damn mackerel was walking down the same hall, wrapped in dirty bandages, under disgusting clothes stained with blood that didn’t look like his.

Or maybe it was.

You can never tell with that freak.

His hair was full of dirt, and dark circles hung beneath vacant eyes — somehow worse than last time.

“What the fuck happened to you?” the redhead asked in a hushed tone, even though no one else was around.

Dazai kept walking and Chuuya took two steps forward blocking his path.

“Did you jump into sewage? You look hideous.” Chuuya couldn’t hold back his disgusted expression.

He gets no answer.

“Dazai.”

"..."

“I know asking you this is fucking useless, but…” He sighed in annoyance. “Are you okay?”

There was a pause as if the fishy bastard actually thought about the answer. And boy isn´t that’s a bad sign.

“I’m fine,” the taller boy said.

“Well, you definitely don’t smell fine.” Chuuya stepped back slightly but didn’t move aside.

A shadow of something — flickered across Dazai’s face.

He tried to walk past only to still be blocked

“We have a meeting with the boss in five minutes. You can’t show up like this.”

Dazai finally looked at him.

“Like what?”

He tilted his head with the fakest innocence Chuuya had ever seen.

“Like shit.”

“I was working.” Now, Chuuya has a fully functioning brain and a good pair of ears. This suicidal bastard is never this careless.

Sure, he’s a piece of shit who enjoys making everyone’s lives hell, but he’s missing his fake mischief. And if he can’t even pretend to be annoying, then things are going to hell.

Which is not good at all.

Words has spread like wildfire around the Port about the Demon prodigy´s favorite drinking buddy getting killed, and as surprising as it is that this asshole can grieve for anyone, Chuuya suppose that even a broken clock is right twice a day.

“Is this about him?”

He didn’t even have to say a name.

Dazai didn’t answer.

And that was enough.

.

.

.

Enough to piss him off.

“You can’t just do this and expect no consequences.”

“Who says I’m not expecting them?”

Chuuya stepped closer, against his nose better judgment.

“Is this self-punishment or something? Is that what you’re doing?”

The bastard laughed —.

“Chibi! I never knew you could be so bold as to insinuate I’m into that. What a kinky acusation.”

“I’m not acusing you of that. I’m worried, jackass!”

And of course.

That seemed to be the wrong thing to say.

“Watch it"

Chuuya blinked.

“What?”

“Have you forgotten you’re under my orders now?”

The words fell heavy onto the shining floor.

It was true. Dazai is an executive now. The boss’s right hand. A demon who commands thousands under the Port Mafia.

He hasn’t used that against Chuuya in years.

The loss really fucked him up, huh?

“Are you trying to intimidate me?”

“I’m reminding you of this organization’s hierarchy.”

“We’re not on a mission. The hierarchy exists when we’re working.”

“We are always on a mission"

“I don’t care about that,” Chuuya crossed his arms. “I’ll call out your edgy shit whenever I want. And right now I’m calling out that you might miss your friend.” 

That’s when the redhead saw it.

Dazai’s breath faltered, his hands trembled and for a moment, real grief flashed across his face making a wave of genuine concern and horror come to Chuuya.

This is worse than he thought.

Then the phone rings.

Mori.

Mori is waiting.


 

He knew they would be late.

If Dazai-kun is involved, everyone will be late. Getting rid of Oda Sakunosuke would've proved harder if Dazai had been punctual. Granted, Mori cheated a bit by delaying the boy himself...

But as tragic as the loss of such a good man was, It had to be done.

“Come in,” Mori says before they knock. And the door slides open.

The doctor’s office is warm, clean with the faint scent of coffee, wax and old books filling the room. Then there’s Dazai.

Stained and making the place reek.

Mori wrinkles his nose a bit when he leans forward, elbows on the desk, fingers interlacing like he always does.

“I assume I didn’t interrupt any of your teenage dramas"he says smoothly. “I’m glad to see you functioning regardless of… everything.”

Dazai of course doesn’t greet him. But at least Chuuya stands still and respectful.

“We have a situation.”

Dazai´s eyes darkened even more, making Mori a victim of those empty and gnawing voids.

The boss barely tilted his head, looking at the bandaged boy up as if he was merely a small inconvenience 

Who might or might not snap and kill him in his sleep.

“Oh, Dazai-kun,” his tone turns sickeningly sweet. “Perhaps next time you could bathe before coming in but that’s not what concerns me.” Even with the awkward silence. Mori chooses to keep going anyway. “If I wanted spotless appearances, I’d hire models. Not that it isn't important to have a good presentation, but I understand—"

“The mission” dazai deadpanned.

“Oh, straighforward I see— you know I adore that about you!”

A report slides across the desk.

“We have an individual without an official ability record. All we know is that he can make people disappear”

Chuuya frowns.

“He’s responsible for at least six incidents involving multiple of our men,” Mori continues, tapping the image of a young man with long white hair. “Witnesses report visual distortions and structural collapse around the victims.”

“Any idea what the ability is?” Chuuya asks.

“We have no idea. None of the victims have returned to us.”

Dazai rolls his eyes.

“So we’re going in blind?”

“I trust the creativity of my best assets,” Mori smirks. “Even if one of them has been… awfully distracted lately.”

Chuuya seems to shudders slightly. Not even bothering to hide the awkward look he sends towards his partner.

“It shouldn’t be a problem. Dazai’s ability will protect you both.” The boss reassures them and stands, approaching the two.

Dazai meets his gaze.

“Elimination or capture?”

“Depends on his cooperation. I’d prefer capture. His ability may be useful. But don’t sacrifice the mission integrity for recruitment.”

“The report mentions backup.”

“Remote observation. We’ll intervene only if strictly necessary.”

Dread flickered across Chuuya’s face. 

Backup for them?.

Dazai was suspicious too.

The boss shrugged and returned to his chair, next to his dear Elise, who was still drawing on the floor.

“You both can go now.” His voice softened, directed at Dazai. “Do your best. It would be saddening if you died before capturing our target.”

Dazai let out a dry laugh.

“How sweet of you.”

“I try to be a good man” Mori replies with false modesty.


They end up finding the man at an abandoned train station.

Once the Mafiosos made sure he was alone they approached as cautious and close to eachother as they could.

“I knew they’d send you,” The man said calmly as red smoke curled around them.

Dazai steps forward, No Longer Human easily dispersing the smoke.

“You seem to have experience sending people away"

“I glad you could notice that. But I simply send them elsewhere.”

The air shifts.

The blue glow cuts through the red.

Nothing happens.

Soukoku expected nervousness from the man. But the white-haired man smiled pityingly.

“You’re don't seem to be nullifying the right thing.”

The ground warps.Walls bend and stretch. Surprisingly affecting the two of them.

Chuuya launches upward, aiming for the whitehair´s head.

His fist passes through empty air.

And No Longer Human fails to stop it in time.


Sakunosuke Oda hated nightshifts

The night he left the commissary. The report had been ordinary enough: lights spotted inside a building that had been closed for more than ten years—an old private laboratory once tied to illegal genetic experimentation.

Most likely a bunch of teenagers doing graffiti, urban explorers, homeless people or even traffickers searching for old equipment to resell. He doubted the place even had electricity anymore, so whoever was inside must have brought their own lights.

Nothing extraordinary.

At least, he hoped so.

It had been a heavy week—cases involving missing children, complicated paperwork, the usual headache of working alongside licensed heroes who believed police officers were unnecessary...

One of his boys had come by the station earlier that day, visiting with his new family after finally being adopted. Which was the only pleasant thing of his evening.

Oda had a habit—one his coworkers politely pretended not to notice—of getting too involved with the orphans who passed through thesystem. Even though he was rarely able to foster children himself due to the demands of his job, he still helped them with homework, sometimes bringing meals or small toys just to make their lives a little less difficult.

That was why, as a small compensation for his hard week and good deeds, he allowed himself to think that maybe tonight would be quiet.

He should have known better.

.

Once outside the laboratory, he immediately noticed the lights. The place did have electricity after all.

That alone made his shoulders stiffen.

He approached the entrance with his gun already drawn. The metal door creaked faintly as he pushed it open, the smell of rust and old greeting him first. Inside, dust floated through the beams of artificial light.

Bright, strong lighting that just looks wrong in a place so empty and quiet.

“Police,” he announced firmly. “If someone is here, come out with your hands up.”

Nothing.

He moved deeper into the building, activating his quirk—enough to predicting a few basic threats beyond doors and corners.

Nothing.

Empty hallways. Empty rooms.

Until he opened one door and froze.

A room lined with metal beds, leashes bolted to the frames just in front of him. The sight made something ugly stir beneath his ribs.

“Bastards,” he muttered under his breath—whether to himself or to the monsters who had funded this hellhole, he wasn’t sure.

He moved on.

He had seen places like this before.

He told himself this one was empty. It had to be, Its been closed for over a decade. He was still a student when the whole thing came out. Most of the children of the case grew to be adults which does soothe him.

Then he heard it.

A small shift.

Not the scurry of rats nor the wind sneaking through the broken windows.

Something quieter

Breathing

His body tensed instantly. Gun raised. 

“Police. Come out. Now.”

His quirk swept past a few seconds before getting into the room where the sound came from.

And that’s when he saw them.

Two small shadows inside a single cage.

Children.

The horror struck him clean in the chest, stealing his breath for longer than any gunshot ever had. For a split second, he couldn’t even process what he was looking at.

He lowered his gun immediately and reached for his comm.

“I need backup,” he whispered sharply. “Possible child endangerment. Two minors located inside the facility. Unknown hostiles still at large.” If the children were here, then someone had brought them here.

And he would not risk two frightened, fragile kids getting hurt because he failed to anticipate a threat.

“I repeat,” he said urgently. “Possible minors on site. Requesting immediate hero reinforcement and medical support.”

His eyes never left the cages.

One of the children shifted slightly.

They looked—

Disoriented.

Older than he first thought. Teenagers, maybe. Thirteen. Fourteen.

Terribly hurt.

One of them stood half a step in front of the other, shoulders squared despite his thin body.

He's only a small malnourished teen in a white dirty gown with a faint red glow around his body

The other kid he seems to be slieding looked so hurt that Oda almost thought he was a dead body.

Sakunosuke’s grip on the comm faltered.

He slowly crouched down, lowering himself to their height, keeping his voice steady and calm—the same tone he used with frightened foster kids.

“It’s okay,” he said gently. “You’re safe now.”

The protective one didn’t move. He looked bewildered at the officer in front of him.

The other looked like he might shatter. rigth there.

Whatever had happened here, whatever had put that look in their eyes. Oda was already too late to prevent it from happening

And he hated that feeling more than everything.

Notes:

So yeah, backup might be hawks, or the hosu police chief If I want to make everything worse.

Is the lab in hosu?.

It is now.
It might come in handy later

Oh, and the perspective from chuuya and dazai waking up in the lab comes next chapter.

Probably.

(I don't like how I wrote this so I might rewrite over the chapter one day)