Dangan Who - Series One

Natsumi and Hajime are students at Hope's Peak Academy Reserve Course, one day, Natsumi was saved from an alien disguised as one of her classmates by Nagito Komaeda, the "Super High School Level Lucky Student" of Class 77-B. After him and Hajime came to save her, Nagito reveals to the two that his identity is false. In reality, he's the 16th reincarnation of an alien, who can travel through time, known as "The Doctor" and his title at Hope's Peak is "Super High School Level Time Lord".