Koro-sensei is the protagonist of the Assassination Classroom saga.He was once a legendary assassin, discovering he had a talent for killing and an inborn lack of empathy. He was eventually captured and sent to a laboratory where a series of experiments were performed on him, transforming his body into a mass of tentacles. He begins to learn compassion and empathy from a female intern, a teacher named Aguri Yukimura, whom he becomes close to. Unfortunately, in an accident that destroyed the moon, Aguri was killed and he broke free.He revealed himself as the moon's destroyer to the world, and offered governments a chance to kill him, under the condition that he is allowed to be the homeroom teacher of class 3-E (Aguri's class) until the end of the year, when he will destroy the Earth - unless he is killed. He is dedicated to his task as a teacher and imparting his knowledge of assassination to the students, despite knowing full well that he himself is their target. However, he is able to connect with each student individually- all of his students like and respect him despite knowing of his destructive power.He is able to move at a maximum speed of Mach 20, which allows him to travel across the world in a short amount of time and makes him a hard target to hit. He is also highly intelligent to the point that he could teach almost every subject to all of his students single-handedly. He does however have a number of weaknesses, mainly to special rubber knives and BB pellets specifically designed to work against his body.Koro-sensei's name is a pun on the words korosenai ( unkillable ) and sensei ( teacher ). Show less «