Netherworld Investigator - Chapter 518

A man reincarnates in the body of a boy who suffered a tragedy, only to realize that he is in the world of My Hero Academia. What's even stranger is that his quirk seems to have the abilities of Nen and Haki.

Inexplicably reborn in the year 2003, having failed terribly in his previous life, the prevailing concern with Xu Tingsheng, that stands above all else, is none other than her. But alas, he is just months away from entering university, while she is but in her first year of junior high… Regarding this, all he can do is wait silently…for now.

Ancient existences wake up in the abyss, demons whisper in people’s ears, unknown horrors erode the spirit, and madness breeds in the darkness of people’s hearts.

But it is not only darkness that descends on this world.

There are heavily armed dark knights walking in the dark to judge crimes; tight-fitting supernatural beings wandering between buildings to act as friendly neighbors; The impossible god on earth, the “S” symbolizing hope shines like the sun on his chest…

No one could have imagined that behind all of them, there was just a player sitting in front of a computer screen holding a keyboard and punching hard.

- Description from novelbuddy

The main character Lei Yu does not have the ability to practice his family’s martial arts. He gets stepped on and tossed around. Due to certain reasons, he leaves the family, coincidentally gains an ability, and makes his own path to becoming an immortal.