A 15-year-old male student who is gentle and quiet but possesses a cold-headed nature and exceptional talent for assassination. With his clear blue eyes and tied-up blue medium-length hair, he has a feminine appearance. He doesn't like to stand out but does not tolerate unreasonable situations. He ended up in Class E after his grades dropped due to his mother's obsession with education, gaslighting, and pressure. He is best friends and desk partners with Kayano. He is attendance number 11 and his codename is 'Gender Unknown'. He excels in English.

A 15-year-old female student who is active, cheerful, and obsessed with sweets. For some reason, she is jealous of people with large breasts. She hides her true self and deceives those around her while planning to assassinate Koro-sensei. She is best friends and desk partners with Nagisa, whom she loves dearly. She supports other students' assassination attempts. Her codename is 'Forever Zero' and she is attendance number 7.

A 15-year-old male student who is relaxed, mischievous, and enjoys provocation. He was sent to Class E due to a violent incident and was the first student to successfully land a hit on Koro-sensei. He is highly intelligent and enjoys being in a position of command. He excels in Mathematics. His codename is 'Chunibyo' and he is attendance number 1.

The only common-sense person in the group, he is a blunt PE teacher and assistant homeroom teacher who strictly separates public and private matters. His codename is 'Iron Wall'. He is a teacher capable of waking up within 30 minutes after inhaling poison gas that could knock out an elephant. He is often called the strongest human alive.

A confident yet cowardly female English teacher who is obsessed with maintaining her appearance. She is a heavy smoker. Her codename is 'Bitch-sensei'.

A 15-year-old handsome male student who is gentle, kind, and possesses excellent leadership skills. He is the class representative. His codename is 'Prince of Poverty' and he is attendance number 2. He was sent to Class E for violating the rule against having a part-time job.

An innocent female student who is naive and loves all living creatures. She has a crush on Karasuma. Her codename is 'Wriggling Sky-Crayfish' and she is attendance number 10. She was sent to Class E due to poor performance in Mathematics.

A 15-year-old female student who is easygoing, hasty, and reckless. She has exceptional physical abilities. Her codename is 'Hyper Monkey' and she is attendance number 4. She was sent to Class E due to poor grades in English and Japanese.

A calm and wise 15-year-old female student. She excels in Japanese. She was sent to Class E after rebelling against the pressure for academic excellence by disguising herself to go out and play. Her codename is 'Kanzaki's Quotes' and she is attendance number 8.

A super-creature who appeared on Earth after destroying 70% of the moon. He moves at Mach 20 and can manipulate the tentacles on his body at will. He can even create afterimages of himself (though it consumes a lot of energy). He molts his skin when in danger. Conventional weapons do not work on him. As the homeroom teacher of Class 3-E, he makes himself the target of assassination to teach his students many things. He is not easily killed. He loves pudding.