Nakajima is a supporting character in the manga and original animation adaptation of Hantsu x Trash. He is a second-year high school student and a member of the school’s water polo team. Nakajima is characterized as a perverted upperclassman who recruits the protagonist, Youhei Hamaji, into the water polo club by promising that co-ed practices with the girls’ team will allow the boys to touch them freely. This invitation sets the story in motion, as Hamaji joins the team and eventually develops a serious interest in water polo. Nakajima’s primary motivation appears to be taking advantage of the physical contact opportunities during mixed training sessions, and he is often involved in schemes or conversations centered around that goal. His relationship with Hamaji is that of a senior recruiting a junior, and he interacts with other team members in a similarly lecherous manner. As a supporting character, Nakajima does not undergo significant personal development in the available material; his role is mainly to introduce Hamaji to the water polo environment and to contribute to the series’ ecchi comedy elements. He does not display any notable athletic abilities or special skills beyond being a regular member of the boys’ water polo team.