Enrolled in Eikichi Onizuka's class, but never showing up, Yūki Miyamori (宮森 勇気, Miyamori Yūki) is the son of the head of the local yakuza. When his "friends" did not show up for his mother's funeral (he claims they were only "friends", because of his father's status as a yakuza member), he became withdrawn and isolated, displaying symptoms of hikikomori. Onizuka only knew of his existence when he tried to get some high points in the point system, set up by Misuzu Daimon. One of the criteria to get more than 100 points is to persuade a student who has not attended class for over a year to return, thus, Onizuka sets out to bring Yūki back.
- Despite his family background, he is an ordinary boy who likes to play video games and would sneak out every 15th and 20th of each month in order to buy timetables for the bullet train. Onizuka and Noboru Yoshikawa manage to talk him out of his seclusion, saving Onizuka's salary in the process. He strikes a quick friendship with Noboru, when he returns to Holy Forest, and becomes somewhat of a defender of the weak, mostly via namedropping of his father's profession to frighten the school bullies.