Fukujirou Yasunaga

First appearance: Chapter 1 Name revealed: Chapter 77 This 53-year old-Japanese history teacher is also Kenichi's homeroom teacher. He and Kyōko Ono pay a visit to Ryōzanpaku to check out rumors that Miu is living with another student although the misunderstanding is eventually cleared up. He is a huge fan of Koetsuji's work and refers to him as sensei. His shiny bald head is commonly used on jokes, such as when Niijima recognizes his head through its shine from far away while seeking help after himself, Kenichi, Miu and Tanimoto get lost during their school trip to the snow due to Jihan's attack.