Manga

Korosensei is a central character in the manga series Assassination Classroom, first appearing in the inaugural chapter.

Originally a human assassin known as the Grim Reaper, he underwent a transformation that granted him immense power and a distinct octopus-like appearance. The circumstances behind this transformation and his motivations are gradually revealed throughout the series.

Korosensei is the homeroom teacher of Class 3-E at Kunugigaoka Junior High School. He claims responsibility for destroying a large portion of the moon and threatens to destroy the Earth within a year unless the students of Class 3-E assassinate him. He simultaneously instructs his students academically and provides them with the skills and opportunities necessary to potentially kill him, creating a unique and complex student-teacher dynamic.