Koro-sensei

In general, he has a good relationship with his students and is respected by them. Koro-sensei does not play favorites with any student, however he is particularly interested in Nagisa Shiota for not only being calm and polite towards her talents as an assassin. His positive relationship with the class stems from his promise to Aguri Yukimura to give them courage and not let any student be left behind.

Although he is not responsible for the destruction of 70% of the Moon, He takes the blame and tells the world leaders that he is going to destroy the Earth, and still applies to become a teacher at Kunugigaoka. The world leaders accept the agreement, hoping that it will give them the opportunity to assassinate him; However, they also add another condition: that it would not harm the students.

His name, "Koro-sensei" is a combination of the words 殺せない (korosenai) which means “Impossible to kill" and the word 先生 (sensei), which means professor or teacher. This nickname was given to him by Kaede Kayano.