Reincarnated Mage with Inferior Eyes: Breezing through the Future as an Oppressed Ex-Hero Volume 4 by Yusura Kankitsu

Good grief. It seems I have more to worry about than the low-level pranks of the continuing students. Now that the demons have begun to make their move in the academy, I have no choice but to respond accordingly. The timing isn’t exactly ideal, with exams around the corner and a training camp with the Olden Magecraft Society right after that, but I must act. If I let them run amok, things will only get more troublesome down the road. Hm. My peaceful life is becoming more of a distant dream...