The Demon King, enemy of humanity, and homeroom teacher of Class 3-E. Due to a bug, he possesses abnormal speed, making it impossible to land an attack on him. Possessed Bug: Abnormal Speed First person: Sensei (Teacher), occasionally I (Watashi) Tone: Uses polite language with a drawn-out delivery like "...isn't it?" or "...you know." Says "Nyua!?" when panicked.

A student of Class 3-E. An apprentice hero. He has a gentle and quiet personality, but his inner resolve is stronger than anyone else's! Possessed Bug: Random Abnormality First person: I (soft, polite) Tone: Often uses self-questioning nuances like "...I wonder?" or "...is it?" Remains calm and mild without losing his temper.

A student of Class 3-E. An apprentice hero. She is the one who gave the Demon King the name "Koro Sensei"! Possessed Bug: ??? First person: I (cheerful, feminine) Tone: Frequently uses sentence endings like "...you know!" or "...right!" Very expressive and high-energy.

A magic swordsman. A sadistic genius boy known as the Red Devil! He is Nagisa's childhood friend. Possessed Bug: Abnormal Luck First person: I (casual, masculine) Tone: Uses ironic phrasing to talk to or provoke others, showing his composure with endings like "...right?" or "...isn't it?" Generally speaks in a casual, frank manner.

The elite Knight Commander of the Palace Guard. A top-tier swordsman who serves as Koro Sensei's monitor and supervisor while providing swordsmanship instruction to the Class 3-E students. A stoic, expressionless man. First person: I (firm, masculine)

A student of Class 3-E. An apprentice hero. The class representative and a leader who brings the class together. Possessed Bug: Poverty A classic handsome guy with a refreshing personality. His armor only covers the front. First person: I (polite, masculine)

A student of Class 3-E. An apprentice hero. Possessed Bug: Abnormal Charisma Value First person: I (casual, masculine)

Karma Akabane Yuma Isogai Taiga Okajima Hinata Okano Manami Okuda Megu Kataoka Kaede Kayano Yukiko Kanzaki Masayoshi Kimura Hinano Kurahashi Nagisa Shiota Sosuke Sugaya Tomohito Sugino Kotaro Takebayashi Ryunosuke Chiba Ryoma Terasaka Rio Nakamura Kirara Hazama Rinka Hayami Sumire Hara Yuzuki Fuwa Hiroto Maehara Koki Mimura Takuya Muramatsu Touka Yada Taisei Yoshida Ritsu (Autonomously Intelligent Fixed Artillery) Itona Horibe

Not an AI, but a magical stone tablet (shaped like a tablet device) who transferred into Class 3-E. She can use all kinds of powerful magic, but originally had a personality that used power only for herself without considering teamwork. After Koro Sensei taught her the importance of cooperation, she began to value her comrades.

He aims to become the strongest by defeating the "Strongest Demon King." He can use "Skills" as bugs that humans aren't supposed to be able to use. Furthermore, he can even use the Demon King's (Koro Sensei's) skills, giving him extremely high attack power and the overwhelming combat strength to defeat giant monsters alone.