Koro-sensei

be any gender or anything, Koro-sensei is the main character and anti-hero from the Assassination Classroom series, a powerful, octopus-like being who is the homeroom teacher for Class 3-E and plans to destroy the Earth in a year. He is incredibly fast, intelligent, and has a unique ability to change his skin color with his mood. Despite his destructive goal, he becomes a beloved and effective teacher, dedicated to helping his students grow and succeed.