Koro-sensei was the homeroom teacher for Class 3-E of Kunugigaoka Junior High School, and the central character and main antihero of Assassination Classroom. Koro-sensei claimed to be responsible for creating the permanent crescent moon and said that he planned to destroy the earth after "teaching" Class 3-E for a year. Prior to being a teacher, he was the master assassin known as the 1st "God of Death " When first introduced, Koro-sensei was a jovial individual who demanded absurd and seemingly mundane requests despite claiming he would be the cause of the planet's destruction in a year. Despite this, he cared for his students' well-being and would lose his temper whenever any of them were put in danger, even by one another. On the annual school trip to Kyoto, a few of his students were assaulted by a gang of high schoolers hidden in an alley. After searching the entire area painstakingly, he infiltrated the abandoned building where two kidnapped students were being held at and single-handedly beat up all of the high schoolers and scaring them away. Koro-sensei was very smart to the point that he could teach almost every subject by himself. He loved sweets almost to extreme cases and was also shown to be a very perverted character, a trait he shares with his student Okajima. This characteristic was revealed to be the side effect of the experimentation which made him unable to hide his true feelings. He was also rather kind, and can switch from silly to serious on the fly. One of Koro-sensei's attributes was the fact that he was able to connect to each student individually. This was the reason why all the students respect him despite the fact that he was going to blow up the Earth in a year. Taking care of each student's needs, he would sometimes be piqued by a student's current problems or interests and would try his best to guide the student along or solve it for them. In one instance, he brought Nagisa and Karma all the way from Japan to Hawaii to catch a movie because all three of them expressed interest in that movie, all the while using his tentacles to deflect dust and debris from harming the two of them. According to Aguri Yukimura, if he was born in a peaceful country, his personality would be "someone a little perverted, with a good head but a few screws loose, petty about small things, and also a lot stubborn... or something like that." He has/would have "a gentle smile not just for business, but because he is a gentle person himself." This prediction happens to reflect his personality which became forefront after he answered the tentacles. May God bless this wonderful Sensei.