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. 

From wimp to warrior. Sort of… 
 
Yeah, Kenichi’s a total wimp. He’s always getting picked on and doesn’t have a lot of friends to stick up for him. The guy needs motivation if he hopes to graduate in one piece. Well, Miu’s the perfect motivation. She’s hot, she accepts him, and she just so happens to live at a dojo with six martial arts masters. You could say fate has led Kenichi to their door, or you could say he was just following the hottie. Either way, he’s about to get whipped into serious shape. If he can survive some hard-core training, he might survive another day at school. He might even score with Miu. Yeah, you could call Kenichi a wimp. But let’s go with underdog instead. 
 
(Source: Discotek)

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A Mexican voice actor. He was married to [Mónica Villaseñor](https://anilist.co/staff/115138/Mnica-Villaseor)

The story is focused on Kenichi Shirahama, an average 15-year-old weakling, whose life turns to Hell with the appearance of the naive, beautiful, and strong transfer student, Miu Fūrinji. After Kenichi witnesses Miu's skills in martial arts, he joins the Ryōzanpaku dojo, the gathering place of those who are truly strong, which also happens to be Miu's home. After beating a karate student in a match, he is soon targeted by all the delinquents in the school. Since then, Kenichi's routine is divided between his hellish training with the masters of Ryōzanpaku, and his fights against the members of Ragnarok, a gang who views him as either a possible ally or an impending threat to their plans. 
(Source: Wikipedia)

Fukujirou Yasunaga