Koro-sensei is a fictional character from the Japanese manga and anime series Assassination Classroom. He is depicted as a yellow, tentacled creature with superhuman abilities, including incredible speed and regeneration. Koro-sensei serves as a teacher for a class of misfit students, tasked with assassinating him before he destroys the Earth in a year. Despite his threatening nature, Koro-sensei is a caring and dedicated educator. He uses unconventional teaching methods to help his students improve academically and personally. His character explores themes of growth, redemption, and the importance of mentorship in the face of adversity.