18-year-old Shin is the leader of class 3-D (17-year-old leader of 2-4 in the manga). He is cool, level-headed, smart, and somewhat introverted. Everyone in the class looks up to him. Shin is feared because of an incident back in middle school, where he punched out a teacher who constantly persecuted a student he believed to have committed a crime, where later he was proven innocent the teacher refused to apologize.
Shin knows right away that something is not normal about their new teacher and keeps an eye on her. He's the first one to find out Yankumi's true identity. In the manga, he is given the alias of "Young Master Red Lion" from Kyou. Shin's father is a high ranking police official.
At the end of the manga, Shin reveals his intent to become a yakuza lawyer, confessing that it's because he loves Yankumi and wants to be with her always.
They are shown to be a couple in the sequel. Shin is a top student of Toudai University, and he has a stable life and job.