Mistaken for a Powerful Figure Reborn in a Bizarre World

An ordinary man with an apparently spotless identity stumbles into the dark side of the real world through a twist of fate. Step by step, he digs up the memories he had forgotten, buried in the deepest shadows.

Along the way, however, he is forced to become the very kind of “person” he never wanted to be.

Short version: Guys, gals, I really was just an ordinary person in my previous life. Please spare me.

(The pacing is a little slow at first. I don't think there are many dealbreakers, and the pace picks up later.)