Yuuya Masaoka, nicknamed "Yūya" or "Yuya," is Natsuo Fujii's friend. He flaunts a flashy, modern personality and playboy tendencies. While maintaining a girlfriend, he readily succumbs to temptation from other women and actively seeks out group dates and parties. A high school student with piercings reflecting his outward style, he also attends preparatory school, showing academic commitment. He secretly shared a past physical relationship with Momo Kashiwabara, a classmate of Natsuo and Rui known for her flirtatious and sexually promiscuous reputation. His role centers on connecting through Natsuo's school network and group activities.