Tensura X MHA {{Fanfiction Crossover}}

Prologue

In the middle of a devastating battle—

"All For One! Your rein ends here!"

Two powerful entities clash in a deserted city.

"Hahaha! All Might! You've come?"

"Precisely, to defeat you and end your evil deeds!"

The sheer force when their fists met was devastating. Countless debris, buildings, anything the like would be blown away. Even a single sweep of the arm from a Villain named All For One was enough to destroy a block of the city.

"Detroit Smash!"

All Might, a superhero, and wielder of One For All, dealt heavy blows to All For One. His power was countering the Villain All For One, endlessly dealing devastating blows.

"Tch, so you've gotten stronger, All Might?"

"In order to beat you, I needed every little ounce of strength."

As the two were trading punches, right when All Might was about to send in another punch towards All For One, a blue-haired girl appeared in between them.

The timing she appeared in was too late, All Might had no way to retract his punch.

"All For One, you bastard!"

"This wasn't my doing, All Might." Contrary to his words, he still retained an evil smile.

The punch had connected, but before All Might could scream in his heart for hitting an innocent civilian, the blue-haired girl turned into blue goo. All Might sent the blue goo flying, which had distracted him.

"You're wide open, All Might!"

"Argh!"

This was the battle between the Symbol of Peace, against the Symbol of Evil. Though this battle may be forgotten, they will clash once more in the future.

***

When I crossed the portal created by Mizari, I suddenly felt drowsy, I couldn't describe it as my memory was hazy. I barely remember anything at that exact moment at all.

<<Master! Hang...in...there...!>>

All I could remember was Ciel screaming something at me. I wasn't sure, but, I think I was attacked by a hostile entity in the middle of the transfer.

Before I knew it, it had come to this...

Why is there a fist coming right at me?!

I could somehow feel that this punch was going to cost me something if it hit.

<<Proposal. Transform into master's slime form to absorb the impact of the hit.>>

Great Idea!

"All For One, you bastard!"

The man whose fist is about to make contact with my body screamed out loud. It seemed that the man didn't want to hit me, and thinks that the other person he was talking to did this.

I got sent flying as the man's fist hits me. Though, he looked a bit shocked and concerned for me, seeing as I had suddenly turned into slime in front of him.

Immediately, I was sent flying far away from both of them.

Time skip. 

5 years have passed since my first arrival in this world. During that time, I got familiar with my new surroundings and adapted to them.

At first, I was ecstatic to see I landed back in Japan. But, it isn't the same Japan I was used to. People had superpowers called quirks, about 80% of the population have them.