Ugawa Sensei is Nao’s ninth-grade homeroom teacher who joins her classmates in bullying her. He is a substitute teacher, since Nao’s class teacher is on maternity leave—and usually, substitute teachers are bullied too. However, Ugawa Sensei realizes that he can ingratiate himself with the popular kids if he joins them in bullying Nao. Nao says that she feels sorry for Ugawa Sensei because she sees that he is a “loser” with bad breath and body odor. She recognizes that his mean actions are a product of his deep insecurities. Despite Nao’s generous analysis of his character, Ugawa Sensei is striking because he is an adult and a teacher, and he should ideally be more mature than the teenagers he teaches. He represents how people who are constantly bullied and trampled on can turn vicious themselves.