Boku No Watashi No Yusha Gakuぼくのわたしの勇者学; 吾等的勇者学; Boku no Watashi no Yushagaku; Our Hero Lessons; Our Hero Studies

It opens when a mysterious strangely dressed person who the kids mistake as a new transfer student enters a peaceful classroom. Much to their surprise he is their new homeroom teacher, among other things…