Ouritsu Majutsu Gakuin no Kichiku Koushi

Setsuna is a perverted instructor who is unable to invoke magic. As a part-time Instructor at the Royal Academy of Magic, he continually tells his students to self-study. The new students who entered the academy with high expectations are disappointed in Setsuna, and judging him to be incompetent, they challenge him to a Geas duel.