[Anime Crossover] The Mafia's Personal Cleaner Works Every Day to Become the Boss

*

As one of the candidates to become the next head of a certain jujutsu family in Huaguo, Youshen Che came to Japan eager to improve himself...

Then he was expelled on his first day of school.

After being expelled, he was robbed.

After being robbed, he ran into a notorious Mafia and became an honorable cleaner: the kind who cleans up curses.

Youshen Che, impoverished, dogged by bad luck, cleaner, young master of a prestigious family: I'm losing it, but I still have to keep working hard.

An excellent heir can use any and all resources to improve himself, wherever he goes.

*

Akutagawa Ryunosuke picked someone up in the Slums.

The person was in rags and in a sorry state, but had a fierce desire for power.

So, just as Dazai had once done, Akutagawa took him in, then decided to teach him just as Dazai had taught him.

Akutagawa: "I haven't earned recognition because I'm not strong enough. So if you fail, it'll be because you aren't strong enough either."

Che: "What a coincidence. I think the same way."

Akutagawa: "I'm going to train you. First, kill every curse in all three buildings, hundreds of floors in total. Then go on missions while killing every curse in Yokohama. There's a time limit, and you don't stop until you're done."

Che: "Great! That's what I was planning, too."

Akutagawa: This guy has the right attitude. He's worth teaching properly.

Che: This guy makes a lot of sense. He's worth learning from.

And so, the two hit it off.

One dared to teach, and the other dared to learn.

*

Everyone in Yokohama and the Japanese jujutsu world knows that the Port Mafia has a new "cleaner".

He once brought jujutsu sorcerers in Yokohama and the surrounding area to the brink of unemployment, and was awarded the "Diligent Jujutsu Sorcerer Award" by the Jujutsu Association.

He also went around beating up people in every corner of Yokohama alongside the Mafia's rabid dog, earning the honorary title of "The Dog's Dog."

Everyone in the Port Mafia also knows that their organization has a new "cleaner".

He was once praised by the entire organization and awarded the "Mafia's Best Cleaner" medal.

He also made a complete turnaround, going from a destitute kid in the Slums to a wealthy young master of a Huaguo jujutsu family, earning himself a generous package of the boss's affectionate (scrutinizing) attention.

They think he wants to become the overlord of Yokohama's jujutsu world, another uncrowned king of Yokohama's underworld.

Che: Actually, I did all of this just to inherit the family business.

Everyone: Do you really think we'll believe that?

*

Recently, the Youshen family in Huaguo received an email from the Japanese Jujutsu Association.

They opened it with anticipation and relief, eager to see just how outstanding their steady, polite, and considerate Third Young Master had become.

Then they saw a wanted poster.

The Youshen family: "..."

The Youshen family: "..." No! That absolutely cannot be their model junior, the Third Young Master!

Meanwhile, battered from head to toe and still bound by Rashomon, the "model junior," Youshen Che, had Akutagawa Ryunosuke pinned to the ground. The red patterns in his eyes reflected the other's fair face.

He let go of the hand gripping the other's neck, leaned close to his ear, and said in a calm, steady voice, "Senpai, in the hundreds of sparring matches you've taught me through, this is the first time I've beaten you."

"So, may I ask for a little reward?"

*

Top, with the top aged 16 and Akutagawa 18 from the start; younger top.

The top starts out clueless about himself, then lets loose and turns naturally dark x becomes dark later. Both are obsessive, crazy strong types.

The top's cursed technique is a little overpowered, but his cursed energy isn't. Usually serious, excessively diligent, ambitious and calculating, with a focus on his career. Throughout the story, the "serious and diligent Third Young Master who always thought he was a good person, but was actually naturally dark" gradually grows into a "gentlemanly scoundrel who openly accepts he's dark and increasingly lets himself go, a wolf in sheep's clothing."

The top won't kill people on a whim (there are objective reasons).

No angst, just healthy, happy thrills. Nothing inappropriate before they are adults.

The career and romance storylines progress together, with a mystery plot as well.

I refuse all writing advice and nitpicking. If you drop the story or dislike something in it, you don't need to tell me.

The worlds merge, mainly Jujutsu Kaisen and Bungou Stray Dogs, with other crossover elements on the side.

Pairing: Akutagawa.

Akutagawa's extreme Dazai fanboy characterization will not change.

Youshen (shen, first tone) is a compound surname.

It will have a very happy ending, so enjoy without worry.

I'll do my best, but OOC is hard to avoid, so please accept my apology in advance.

Theme: A serious jujutsu sorcerer should prioritize serious work