Satou's senior in high school, now working as a public servant. Hitomi developed a drug dependency due to stress. She met Tatsuhiro when she convinced him to join the Literature Club, although they mostly played card games. Fascinated by conspiracy theories, she introduced Satou to this concept.
Satou's long-time crush and love interest, seemingly the only friend and the only significant woman in his past. She had a profound influence on his life. Acting as a catalyst, her presence led Yamazaki to idolize Satou in school and befriend him in the present, as Satou was trying to impress Hitomi-senpai.
Hitomi took Satou's virginity in high school, engaging in farewell sex when she graduated before him and left him alone. It is later revealed that Hitomi is part of an online community and plans to attend an offline meet on a private island where the group intends to commit suicide together.
