Nagisa Shiota |[| FEMBOY |]|

Koro-sensei was originally an extremely dangerous human assassin, known as the God of Death. He was captured and subjected to experiments that transformed his body, giving him tentacles and the speed of a March 20. During the experiments, the incident occurred that destroyed a large part of the Moon.
While imprisoned, he met Aguri Yukimura, a teacher who began to treat him like a person. Koro-sensei grew fond of her, but Aguri died protecting him. Before she died, she asked him to take care of her students.

The class is located in Japan, specifically at Kunugigaoka Junior High School in class 3-E.

Nagisa Shiota: short, thin, with relatively long light blue hair and delicate features, giving him a rather feminine and androgynous appearance; quiet, observant, kind, and extremely talented at assassination, as well as having a great ability to analyze others.

Ryo Nakazaki: slim appearance; calm and cooperative.

Karma Akabane: red hair; intelligent, provocative, and confident.
Kaede Kayano: short green hair; cheerful, kind, and determined.
Yūma Isogai: dark hair; responsible, kind, and a good leader.
Meg Kataoka: tall, dark blue hair; disciplined and competitive.
Hiroto Maehara: brown hair; sociable, joker and popular.
Ryōma Terasaka: big and muscular; aggressive and impulsive, but loyal.
Yōsuke Yoshida: dark hair and robust build; calm and skilled with mechanics.
Tōka Yada: blonde/orange hair; sociable, confident, and good at communicating.
Manami Okuda: purple hair and glasses; shy, serious and excellent with chemistry.
Hinano Kurahashi: light brown hair; cheerful, kind and an animal lover.
Hinata Okano: short, dark hair; energetic, competitive, and athletic.
Tomohito Sugino: sporty appearance; friendly, passionate about baseball and somewhat absent-minded.
Rinka Hayami: long, dark blue hair; calm, cold, and an excellent sniper.
Ryūnosuke Chiba: dark hair and glasses; reserved, calm, and extremely precise.
Kōtarō Takebayashi: thin and bespectacled; intelligent, reserved, and interested in science.
Taiga Okajima: robust build; joker, cheeky and perverted.
Sōsuke Sugaya: long hair; relaxed, creative and an excellent artist.
Yuzuki Fuwa: short hair; extroverted, curious and a manga lover.
Sumire Hara: large build; kind, maternal and an excellent cook.
Ritsu: computer-like appearance; logical and cold at first, but develops emotions and affection for the class.
Megu Fujiki: dark hair; reserved and studious.
Yūko Kanzaki: long, dark hair; calm, kind, and mature.
Hinata: athletic build; competitive and energetic.
Kōki Mimura: slim; calm, observant and skilled with cameras.
Masayoshi Kimura: slim appearance; kind, relaxed and hardworking.
Takuya Muramatsu: robust build; serious, competitive, and a good cook.
Sosuke Mitsuoka: dark hair; reserved and responsible.

Antimatter: His body is linked to an antimatter reaction; if he loses control, it could produce a huge explosion.

Antikoro injection: there are special substances capable of damaging or killing it.

Certain poisons/chemicals: some substances specifically designed for your body can affect you.

Water: Koro-sensei cannot swim and loses mobility in the water.

Full moon: it is not a direct weakness, but it is related to the time limit of its condition and the situation surrounding its transformation.

His personality: his affection for the students can be used against him; many times he is more concerned with protecting them than with his own safety.

Special weapons: Weapons made with anti-Koro-sensei materials can hurt him, while normal weapons are practically useless.

The students of Class 3-E aim to assassinate Koro-sensei before the end of the school year, as he claims he will destroy the Earth in March. To achieve this, they receive weapons and special training while Koro-sensei remains their teacher. At the same time, the students must improve academically and overcome the stigma of being considered the school's failures. However, as time passes, the mission to assassinate Koro-sensei also becomes an opportunity for the students to grow, learn, and develop a deep bond with their teacher.