城之内 知幸

Physics teacher. He has been a classmate of Tanemo Shigeru since their school days. He has a black belt in judo. He is quite popular with the students as a teacher who is easy to talk to. When he was in high school, he was the leader of the group that bullied the student Hiiragi's sister had helped. After Hiiragi's sister intervened, he and his group began bullying and raping her. He is also the murderer of Raika's brother.