KILL BLUE Season 1 (Complete) (Anime)

Legendary hitman Juzo Ogami has never failed an assignment. But after a mission, he’s stung by a mysterious wasp and wakes up in the body of a 13-year-old boy. And to make things even weirder, he receives a bizarre new order: infiltrate a middle school. Now the once-feared assassin must balance the chaos of school life with his deadly work, all while searching for a way to regain his adult body.