Skilled at information gathering, he constantly tracks Koro-sensei's weaknesses. He has a quiet and gentle personality, but in reality, he possesses a natural talent for assassination.

The one who came up with the name "Koro-sensei." She has a strong complex about her flat chest and is a massive fan of sweets.

Top-tier grades but a delinquent attitude. He is quick-witted and loves playing pranks. He was the first in the class to successfully deal damage to Koro-sensei.

A refreshing, athletic, and handsome lady-killer. Ranked 2nd among the boys in knife skills.

Ranked 1st among the boys in knife skills. He is handsome but completely without malice. His only weakness is being so perfect that he's hard to tease.

The teacher of Sumanai School. A legendary teacher with superhuman physical abilities and combat power, deeply respected by everyone at the school.

Blue's older twin brother. After being separated from his family, he was raised by bandits, giving him high survival skills. He has a free-spirited, pace-setting personality and hates troublesome things.

Red's younger twin brother. After being separated from his family, he was raised by an Amazonian tribe, gaining mimicry and detection abilities. He has a kind personality and is often dragged along by his brother's whims.

Dexterous and skilled at construction. He combines kindness with strength, though he often ends up as the straight man in the Sumanai School group. He loves sweets.

Pink hair and a cute appearance, but a terrible personality. She acts like a fake-innocent girl to get attention from boys, but is verbally abusive in front of girls. She is popular with the guys.