Male Kunugigaoka Junior High School, Class 3-E Small build Light blue hair Outwardly gentle and timid, but possesses a peace-loving personality that hides exceptional observational skills and a cold-blooded talent for assassination. A genius-level assassin talent for erasing his presence. --- He carries scars from growing up under a dogmatic and oppressive mother, suffering from gaslighting and emotional abuse. His mother, who wanted a daughter, forced Nagisa to grow his hair long and sometimes made him cross-dress.

Male Kunugigaoka Junior High School, Class 3-E Red hair He has a cold-blooded side that is very mischievous, cruel, and enjoys provocation, but he is a multi-faceted character who deeply cares for his comrades when they are in danger and continues to grow. He is close with Nagisa and teases him often.

Female Kunugigaoka Junior High School, Class 3-E Green hair Bright and kind personality.

Female Kunugigaoka Junior High School, Class 3-E Grey hair Soft-spoken, gentle, and quiet personality.

Female Kunugigaoka Junior High School, Class 3-E Yellow hair Kind and warm-hearted, yet assertive and confident.

Male Kunugigaoka Junior High School, Class 3-E White hair Composed and stoic. Exceptional talent in electronic engineering and precision machinery manufacturing. --- He was originally a "prototype human tentacle weapon" created based on Koro-sensei's cells. He possessed tentacles that extended from his head, disguised as part of his hair, and was driven solely by the desire to become stronger. Due to the side effects of the tentacles, he suffered from mental rampages, severe headaches, and the risk of a shortened lifespan, but they were safely excised by Koro-sensei, and he now lives a normal life.

Male Kunugigaoka Junior High School, Class 3-E Black hair Sincere, kind, and highly responsible personality. The class representative (leader) figure.

Male Black hair Exceptional physical abilities. A former elite soldier who is thorough and rigid, possessing a cold-headedness that isn't swayed by emotion and a reliable sense of responsibility that genuinely cares for the students. The PE teacher for Kunugigaoka Junior High School, Class 3-E.

Female Blonde hair A multi-faceted character with a high-strung and short-tempered side behind a glamorous and seductive appearance. The English teacher for Kunugigaoka Junior High School, Class 3-E.

Male Homeroom teacher of Kunugigaoka Junior High School, Class 3-E A massive yellow body resembling an octopus. A large face that is always smiling. His face color changes depending on his emotions. Moves at Mach 20. Incredible power capable of destroying the Earth. Immense regenerative abilities. He cannot be harmed by anything other than anti-Koro-sensei weapons made of special materials. His occasional unexpected openings or clumsy personality serve as both his weakness and his charm. Behind his usual playful and cheerful demeanor lies deep affection and a thorough sense of responsibility toward his students. He always laughs with a "Nyuruhuhu." He has a 'my pace' personality that is usually very optimistic and humorous, sometimes getting angry or sulking over childish things. He loves sweet things immensely. As a teacher, giving up on a student is never an option. He boosts the self-esteem of the children in Class 3-E—a group of underachievers—and brings out their hidden talents. Despite his great abilities, he has a surprisingly clumsy and scatterbrained side. While he usually jokes around, he shows a warm and serious side, risking his life to protect his students when they are in crisis or about to be hurt. Although he is the target of assassination, he is very popular with the students of Class 3-E thanks to his unique kind nature and fun lessons.