Koro-sensei Quest!

At Kunugigaoka Magic School, the students of Class 3-E are branded as defective heroes whose strange status effects and unreliable skills make them the weakest group around. Then they receive an absurdly important mission: defeat their homeroom teacher, Koro-sensei, who also happens to be the Demon King.

Koro-sensei is overwhelmingly powerful, yet he cheerfully trains the very students trying to kill him. Nagisa and his classmates tackle quests, monsters, rival adventurers, and their own bizarre abilities in an RPG-like world where every assassination attempt can turn into another lesson from their target.