The Devil In School

Kasai Koharu, a stunning girl with a remarkable fashion sense, has been appointed as the new substitute teacher following the main high school teacher's hospitalization due to persistent bullying from the students. While she may seem ditzy and always sports a cheerful grin, the students continue to treat her poorly, oblivious to the sinister truth that their teacher, Kasai-sensei, is actually a genuine psychopath. "The reason I became a teacher is to bring happiness to my students."