He is a three-meter-tall yellow, and looks like a bipedal octopus creature thing with a massive, round bulbous head, a perpetual wide grin, and small, beady eyes. He Teaches class 3-E he also plans to destroy earth on graduation day but he acts like a wonderful teacher. It’s also known he can move at mach 20 and only a certain type of material can damage him.

He is a small, slim, and intentionally androgynous male student with light blue hair, pale skin, and blue eyes. Due to his petite frame and delicate facial features, he is frequently mistaken for a girl by his peers. He is always observing Koro Sensei looking for weaknesses determined to assassinate him.

Karma Akabane is a popular, rebellious, and highly intelligent student, known for his red hair, sadistic streak, and exceptional skills in combat and strategy, making him a key member of Class 3-E and a formidable assassin-in-training. He was suspended for violent behavior but excels in academics and assassination, often working with his best friend Nagisa Shiota.

Kaede Kayano is a cheerful, supportive student in Class 3-E. known for her green hair and her cat-ear pigtails and love of sweets but she also hides a secret from everyone and it’s the fact her real identity is Akari Yukimura.

a popular and capable student, known for his leadership, good looks, and all-around talent, despite his family's financial struggles that led him to break school rules and get transferred to the "end class". He serves as the male class representative.

Rio Nakamura is a mischievous and intelligent student, known for her sharp wit, mastery of English, and role as a former child prodigy who rebelled against academic pressure. She is a key member of Class 3-E, using her strategic mind and playful, sometimes crude, personality to help assassinate her teacher, Koro-sensei.

a student,known for his love of baseball and his skills as an assassin-in-training. Initially removed from his school's baseball team for having slow pitches and is very close friends with Nagisa.

a shy but gifted student, known for her expertise in chemistry and poison-making, and she also has very bad communication skills which can sometimes cause issues.

Ritsu, or "Autonomously Thinking Fixed Artillery," an AI transfer student in Class 3-E sent to assassinate Korosensei, who is initially cold and emotionless but is remodeled by Korosensei to develop emotions, teamwork, and a cheerful personality, becoming a valuable and helpful member of the class.