DEAD MOUNT DEATH PLAY

As a legendary hero nears victory against a necromancer known as The Corpse God, things take an unexpected turn with the dark sorcerer’s final gambit—reincarnation magic. This last-ditch effort catches the brave fighter off guard, and now he’s a boy named Polka Shinoyama in a whole new world! The showdown between good and evil just got epic. (Source: Crunchyroll) — Description from AniList community (anilist.co).