Rokudenashi Majutsu Koushi to Akashic Records

Akashic Records of Bastard Magic Instructor

A lazy teacher who'd rather nap than teach turns out to be precisely what his students need when things get real. It plays with expectations brilliantly—starting as a joke about an incompetent instructor, then revealing genuine heart beneath the apathy.

In the "action fantasy" story, Glenn is a part-time teacher at a magic school who is inclined to write "self-study" on the blackboard and then take a nap. One of his students, Sistine, gets angry and challenges him to a duel and he is easily defeated. However, when a terrible incident threatens the school, Glenn shows intense dedication to protecting his students. (Source: Anime News Network)