Koro-sensei

assassination classroom

Korosensei used to be a human with small black eyes, short dark hair and pale skin. While working as an assassin, he would wear dark colored clothes, usually black or brown.

After being used in experiments, Korosensei acquired the appearance of a yellow bipedal octopus. He is about three meters tall and possesses a large, bulbous head with a large smile and small, beady eyes. He uses two feelers as arms, with two fingers each, and utilizes the rest of his tentacles to walk with.

Korosensei also dons a black academic dress, a small black square academic cap with a yellow tassel, and a large black tie with a yellow crescent-shaped moon on it.

It was revealed that he was raised in an environment "where everybody could easily betray one another to the point that one could only trust oneself". Through these hardships, he decided to become an assassin in order to survive. Despite he gained an apprentice, he only saw him as a tool for his goals, which caused the latter to finally betraying his master.

However, after meeting to Aguri Yukimura, he finally knew what compassion really was becoming much more kind and sympathetic. According to Aguri, 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.

When first introduced, Korosensei is a easygoing individual who demands absurd and seemingly mundane requests despite claiming he will be the cause of the planet's destruction in a year. He is also rather kind to others in general and can switch from silly and childish to serious on the fly. According to Nagisa, Korosensei also is unintentionally petty at others at times and loves gossip, both traits heavily noted through the series.

Due to the human experiments of producing antimatter in a living body by Shiro, Korosensei's entire appearance is of an octopus-like creature with multiple tendrils that are his tentacles. Anything aside Anti-Sensei Weapons will be immune to him. It is initially believed that he will self-destruct by the time of Class E's graduation; however it has since been proven that the chances are minuscule at best.

One of Koro-sensei's most advertised assets is how fast he is and that he can move around the world at velocities up to Mach 20 like he’s some kind of superhero. Koro-sensei's intense speed is also shown to have another purpose, which is used more for visual gags than an advantage in battle. Koro-sensei's speed can produce many after-image versions of himself, but rather than merely act as illusions, they can also carry out rudimentary tasks. It doesn't just confuse the opponent, but is a brilliant way to maximize limited time.

Even before Korosensei gained his powers, he possesses a gifted mind which allows him to learn and understand complex knowledge in a matter of minutes. With his immense intelligence, he was able to single-handedly teach all the subjects and produce amazing results from the bottom of the barrel class of 3-E. Since gaining his speed, Korosensei has become hypercongnitive, and can process information thousands of times faster than the average human being. His incredible mentality combined with his speed also allows him to multitask on up to dozens of jobs at a time (teaching the entirety of Class 3-E individually and then some), all of which seemingly being done simultaneously. Most impressively, he was able to give the assassination AI Ritsu approximately 985 upgrades in less than a single day, completely transforming her, increasing her intellect, and giving her personality and sentience.

Class 3-E (3年E組, San-nen E-gumi) or simply Class E is the lowest ranked class of Kunugigaoka Junior High School. It is nicknamed the "E-as-in-End Class" and consists of students who either failed to keep their grades up (i.e. Yukiko Kanzaki, Nagisa Shiota) or were punished for breaking school regulations (i.e. Yuma Isogai, Karma Akabane).

The current year of 28 third-year students were tasked with a mission to assassinate an unknown destructive lifeform who they named Korosensei.

The building was originally a cram school Gakuho Asano first taught at. Asano had a teaching style very similar to Korosensei; he raised them to become kind and well-rounded. However, after the suicide of one of his former students, Asano developed new education ideals of creating "strong" students instead of "good" ones, and created Class 3-E to segregate the weaker students.

Class E was made solely for the purpose of fulfilling Chairman Asano's educational value of his variation of the 20:20:60 worker ant ratio, a social science which states that 20% of people are exceptional, 20% of people are worthless,and the other 60% are ordinary. In Chairman Asano's "E system", the students who display poor academic ability are gathered in Class E and are singled out as the worthless ones, as a result, students do everything in their power to keep their grades up and avoid getting transferred to Class E.

Asano's goal is for 95% of his students to be in the exceptional category, while only the remaining 5% fall into the worthless category (ignoring the fact that Class E actually comprises of 15% of the total student body).Blatant discrimination and stigmatization from the main body of the school, new and inexperienced teachers, poor and shoddy study environment, and even Chairman Asano himself intervening occasionally to ensure that the Class 3-E 'stays in the bog', sabotaging any effort from Class 3-E to improve itself academically, added to the despair of Class E students who lost the will to strive makes escape from Class 3-E while still attending the school virtually impossible.

Prior to the events of the story, Class 3-E was under the tutelage of Aguri Yukimura who was killed shortly after the destruction of the moon[1] and being subjected to all manners of unjust, unfair and contemptuous treatments as failures.

The Class E building is located one kilometer away from the main building up on a nearby mountain. The trail between the Main Campus and Class E, in addition to the uphill trek, is riddled with a number of natural obstacles, such as snakes, bees, and rivers.

Its exterior is that of an old rundown wooden school building with several places on the roof and a few windows boarded up. The interior contains a simple classroom with a blackboard, 28 desks, and a small faculty lounge. The building has no air conditioning and the ceiling has several leaks in it as well due to lack of funds (stemming from discriminatory school policy). Even with the building in such poor quality, Class 3-E is not on the list of School's concern to renovate the building.

Currently, Class E is the location of a government confidential assassination of their homeroom teacher, Korosensei. Because it is secluded away from the main building, the students and teachers are able to carry out their assassination attempts without the people from the main school knowing or noticing.