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Published:
2026-06-11
Updated:
2026-07-05
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17,381
Chapters:
6/?
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How to Become a Detective (The Hard Way)

Summary:

“We are not accepting applicants at this time. Leave now or I’ll have security make you.”
“But I’m already an applicant, I literally have a meeting scheduled and—”
The door to the office slams shut.
This is the only place that offered an interview, and now it too has rejected him.
Ranpo knows that the secretary is suspicious, but the police wouldn’t believe him. Not unless he uses his Gift to pinpoint the evidence. But doing so without the permit— sitting, unsigned, on the president's desk— would get him in trouble. Trouble that he can’t afford to deal with.
Not when the cops would ask him where his parents were.

---

Follow 14-year-old Ranpo on his journey of trying to become a gifted detective in a world filled with quirks, villains, and unfairly restricting laws, with war staining the past, and a new one looming over the horizon.

This is not quite the Ranpo you know.

[July 7th: Currently undergoing MAJOR editing as I have now read the Untold Origins light novel and BOY does it give me so much more info to work with— I need to edit Ranpo’s personality and update my world building notes :)]

Notes:

There's a criminally low amount of Ranpo-centric BSD x MHA crossover fics for how interesting the implications of him being in MHA are!
The general premise of this fic is 14-year-old Ranpo going to UA, but it’ll take him a bit to get there.

One important worldbuilding thing to note before you start is how I'm gonna handle quirks and gifts. In short, they are different. In practice, both are basically considered to be the same thing for the most part in a legal sense, though gifts do have an air of mystique and mild fear due to one particular thing about them and a certain event that highlighted that difference. This will be further explained throughout the story in parts.

As one final note, having prior knowledge of MHA would help, but is technically optional seeing as Ranpo will end up explaining things whenever they become relevant. You’d probably be a bit confused, but not entirely lost.

Having prior knowledge of BSD— namely the Untold Origins Arc— is recommended. But technically not required.

---DO NOT FEED TO AN AI; that's just basic fic etiquette at this point---

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

Chapter 1: How to Obtain a Permit

Summary:

…The legal way.

Notes:

(See the end of the chapter for notes.)

Chapter Text

After far too many missed train stops and far too long of a walk, Ranpo finally spots his destination from across the street. An older-style building stands out amongst the simplistic ones adjacent to it, the reddish brick exterior giving it a sense of grandness.

He dashes to the entrance, not sparing a second thought to the few people out and about on this drewery day.

He almost collides with some passersby— one with the head and build of a bloodhound, interestingly enough— but he dodges as they run past him and towards the ally to his right in a panic. They have a hand on a radio that they’re speaking into, the accented words unintelligible to Ranpo as they get lost in the wind.

The boy pays the stranger no mind, eager to get started on a stable job that won’t fire him within the week.

The wind picks up, threatening to blow his hat off as his cape bellows to his left, his grip on his messenger bag tightening for a moment. He hastily grabs his hat and opens the door on the right, letting the wind slam it shut for him as he bounds inside, the noise of the street and oncoming storm muffled by the thick wood. Ranpo sighs as he leans back against the door, fatigue threatening to overtake him as he stares at the long, long hallway before him.

He’s finally here. Fifteen minutes early as well.

Good thing I gave myself two hours to get here…

The teen lets himself lean there for only a moment— he knows that if he sat down, no one would come to drag him up again. His head hurts for some reason, the mild pain concentrated around his temples. The boy rubs his eyes and forces himself to forget about his fatigue for a few more hours, instead thinking about what kinds of snacks a place like this will have out for guests and recruits like him. His stomach growls at the thought.

He could probably ask an assistant to give him a full meal's worth.

Deciding it best to leave his somewhat heavy messenger bag at the entrance, he marches down the hall, past the out-of-order elevator (just my luck), and up the stairs at the end.

One, two, three, four, Ranpo counts as he ascends. He’s out of breath by the time he reaches the top, emerging into a hallway lined with doors. The boy takes a moment to catch his breath, leaning against the smooth wood railing next to him.

The railing was old-fashioned and somewhat ornate, matching with the rest of the building. Ranpo absentmindedly wonders why an office building even has a staircase like this. The style brings an old memory to the forefront of the boy’s mind.

He remembers watching TV with his mother, an old action show playing on the screen as he rolled a hard candy around his mouth, filling it with the taste of blue raspberry and sugar. A man in a suit— the protagonist, a secret agent who he recalls had a history with the boss of the mafia, not that that had been revealed just yet— had leapt down stairs just like these ones to catch up to a criminal.

Ranpo quickly shakes his head. It’s still ten minutes until his meeting starts, but he shouldn’t waste this time loitering in the hallway. His dad told him that showing up early helps build “repoor”… or something. He knows it’s supposed to be important, somehow.

Besides, they’ll have snacks.

The teen starts walking down the long hallway, his footsteps the only thing he hears. Each door he passes has a different name, but the same style. His mind drifts once again for something to distract him from the soreness of his feet.

…They never did end up finishing that show, never got the chance to see the final episode together. It’s not like they didn't know how it would end— his mother especially had a knack for predicting shows beat-for-beat, even including the dialog, something that took him years to catch up to— but it would be nice to sit on the couch with his mom one last time.

A familiar ache grows in his chest. His mind grows quiet, thoughts replaced by vague memories and fleeting feelings.

Ranpo snaps out of his revere when he notices the sight of the street outside filling his view. Pedestrians living their day-to-day life, a few looking towards something out of sight to his left. The wind howls, blowing a random passerby’s hat away, carrying it off to somewhere unknown.

He’s walked straight past all of the doors.

I gotta stop spacing out like that… no great detective gets caught unawares! Ranpo frowns at the glass like it had personally offended him. Especially not by a stupid window… The boy huffs as he turns around to scan the doors for the president’s office. The double doors on his right look promising. He grabs the handles to both doors.

“Greetings!” the boy loudly announces his presence as he swings both of the doors open without a second thought.

A yelp sounds out, accompanied by the sound of a body hitting the floor.

Oops.

Thankfully, the yelp doesn’t sound like a woman’s, so Ranpo ignores the likely-assistant and instead takes note of the office before him.

A prominent desk sits to his right, overlooking the large room, an ornate bookshelf with glass cabinets situated behind it. The middle of the bookshelf is lower than the sides, a large photo in a false-gold frame leaning against the wall sits on top of this lower section. The photo shows a group of people in suits standing behind the desk, the president sitting in the chair in front of them, her white suit marking her as important.

On the desk rests a relatively simple desk lamp and an old-fashioned company phone. A small stack of papers is scattered over the side of the desk closest to the entrance, though most of the papers appear to have been blown off the desk and onto the floor.

The culprit is an open window along the back wall, a part of a whole line of windows looking out over the shorter neighboring building and to the skyline of the city. Curtains frame the windows, all drawn to let the morning light shine through. The wind howls through the opening, its voice shrill and sharp, carrying faint whispers of commotion when it dies down a smidge.

A muffled voice during this ebb draws his attention over to the small lounge on the left side of the office. Past the low table, ornate couches, and locked book cases stands a plain wooden door, no different from the ones found in the rest of the building.

Ranpo feels the hairs on his neck stand on end.

He slowly steps forward and peaks behind the door to his left— the one that didn’t fully open— spotting a man in a trench coat sitting on the floor. Something weighs down the sides of his trench coat, likely some items in internal pockets.

What are you hiding?

The man is rubbing his head, glaring at the boy from beneath his hand. Slowly standing up, he moves in front of Ranpo. The teen instinctively takes a few steps back, just far enough to officially “leave” the office area.

This man does not welcome him.

“What business could you possibly have that gives a brat like you the right to barge in here?” The man sneers.

Ranpo frowns at his wording. I’m not just “some brat”— Standing tall, shoulders back, he responds to the man.

“I’m an applicant for the ‘Quirked Detective’ program.” He pauses for a second, before deciding it best to tack on a “sir,” irritation lacing the word.

The man makes a face at his words.

“What’s with that face?” Ranpo asks before the man can respond. “I’m being polite, so do your job and bring me to the president!” The teen crosses his arms and frowns.

The man’s face flinches, freezing for a moment at the mention of the president. His face is on that photograph, near the back, Ranpo realizes. Not a simple assistant, but is in and familiar with this office nevertheless. An office filled with books— no, records— locked behind glass, and a secondary room connected to it. The pieces click into place. A secretary.

The president had said she was free this whole morning only a day before. She should be in her office right now, preparing for his interview.

The window has no screen.

The pit in his stomach makes itself known, the dull and sharp aches demanding that something be done.

He hasn’t eaten anything in… 20 hours, and that was only a muffin a man at the mall agreed to give him because he bought the wrong thing. That must be why my gut feels bad right now.

“I’m hungry,” Ranpo says before the man can think of what to say, only a short few seconds having passed since he last spoke. “Don’t these meetings usually come with snacks and tea?” He leans forward slightly, glaring at the secretary, the vibrant verde of his irises visible. “Where are they?”

The wind howls.

The secretary’s face pulls taught in a look that’s somewhere between frustration and fear. He grabs the other door and moves to close it, the wind slamming it shut for him with a whistling cry as papers fly around the room. Grumbling, the man calls out to someone behind him.

“Please close the window so I can properly see this lost child out.”

Ranpo’s face scrunches up. I’m supposed to be here though! You of all people should know that, jerk.

Another man emerges from the left side of the room, dressed in a classic professional security guard get-up. The guard calmly walks over to the open window, speaking into a radio along the way, most words lost to the wind and the flapping of pages. The boy can only make out something about an “assassin.”

The window shuts with a deafening silence, all the papers settling down soon after. Something feels caught in his throat.

The secretary turns back to Ranpo. His eyes comically widen as he likely recalls his president’s schedule, before strangely narrowing into something stern.

That took you long enough, Ranpo thinks with a smirk, mocking the man in his mind. Now do your job and hand me—

“We are not accepting applicants at this time. Leave now or I’ll have security make you.”

…Oh.

“I’m already an applicant though,” Ranpo tries. Even if the meeting can’t happen anymore, there is a document with his name on it. One that he’s been trying to get a hold of for the past few months. “I have a meeting scheduled and everything, I was supposed to receive an official license today, can you at least let me grab the document I need so I can—”

The door to the office slams shut.

 

This is the only place that offered an interview— one of the few that even responded, really— and now it, too, has rejected him (of course of course of course no one wants me, no one alive wants me, not even he did in the end, they all—)

Well, their loss.

He thinks that the president would’ve wanted to see him, but…

It’s clear that she’s no more.

The sound of sirens approaching slowly fills the air, drowning out all other noise except the howling of the wind carrying it. Ranpo knows that the secretary is suspicious, but the police wouldn’t believe him. Not unless he uses his Gift to figure out the details and to pinpoint the evidence.

But doing so without even just the provisional permit— sitting on the president's desk, too heavy for the wind to carry off, too low in the stack to be signed— would get him in trouble. Trouble that he can’t afford to deal with.

Not when the cops would ask him where his parents were.

Not when they would want to speak to his legal guardian upon hearing the answer.

Not when they would drag him back to that place when they find out.

Still, he thinks, It’s only fair that I tip them off…

It’s the least he could do for the newly deceased.

The boy sighs, turning away from the door, from the permit, his permit, his future, sitting unsigned and all but legally useless on that desk— but oh so easy to make useful, all he needs to do is forge one, simple, single signature, it’d be his only option at this point, and there’s plenty of examples to base it off of all over the room—

If only her murderer didn’t see me…

Ranpo knows that even though the man won’t remember his document, let alone the fact it was unsigned, he would still testify against him in court if he were to forge a signature.

Anyone who worked in or for the police would, and it would only be a matter of time before someone questions the authenticity of the paper anyway. He should’ve known that it’d turn out like this, in one way or another.

 

Ranpo knows about the blacklist, and he knows why he’s on it.

Sometimes, in the dead of night when the sky turns gray and still, he finds himself wondering what the reason listed is. How much of it is lies to cover for that prick’s abuse, and how much of it is the truth. How much of it is somehow deserved, for reasons he just doesn’t understand (there’s something fundamentally wrong with me, something almost everyone else can see despite being dumb, Fukuzawa told me it’s just that everyone else is stupid but even stupid people don’t typically reach a consensus like that without some level of truth—).

…It’s not worth Deducing.

Ranpo hears the sound of paper rustling, accompanied by the tell-tale dial tone of a phone call about to be made. The boy feels his vision come back into focus, the world unmuffling a little as he suddenly becomes acutely aware of his current surroundings again.

He belatedly realizes that he’s about to miss his chance, having stood in this corridor for ten seconds too long.

Crap.

Grabbing the rim of his hat, Ranpo sprints down the hall, cape dragging through the air behind him.

The sight of the railing at the end of the hall plants a ludicrous idea into the teen’s head, one that he’s not about to ignore.

Without a second thought, he leaps over the banister.

Notes:

One important thing to note about the worldbuilding of this fic is that this is a fusion of the two worlds, and unlike a surprising majority of other BSD x MHA fics, Yokohama is just... a city in Japan. It's not walled off or a different country or like Quebec or anything, though it does have a few quirks (ironic), such as having the lowest percentage of quirked people outside of some small rural towns, and has a reputation for being quirkist and not funding heroes well. It's unique for sure in that latter aspect, and does have the largest active criminal underworld in all of Japan and also the whole situation of power struggle going on (of which I only learned about in the canon of Untold Origins recently), but Heroes aren't actually barred from entering or anything, nor are they a completely unprecedented sight to see.
There's just significantly less of both them and your typical villains compared to other cities, and especially places like Musutafu.

I headcanon that Musutafu has the largest frequency of villain attacks per area in all of Japan, solely because of the impression that the first episode of MHA gave me. Yokohama, on the other hand, has barely any villains (IE, people who use their quirk or gift to commit crimes, often violently), and pretty much every recurring villain in the city has a gift, not a quirk.
Quirked villains fear Yokohama, while the quirkless often like to move there.

These facts are for a VERY good reason, and said reason is also what gives gifts a bit of a reputation of being more dangerous in general. That, and another thing.