Koutarou Ishigaki  

, 石垣 光太郎

Ishigaki is described as kind, respectful, and friendly in his interactions with teammates and others. He values his role as an upperclassman and provides support for underclassmen. Prior to Midousuji joining the cycling club, Ishigaki and other Kyoto Fushimi members used affectionate nicknames such as "Ishiyan" and "Nobu." Ishigaki is also kind to Onoda during their first meeting by picking up his water bottle and trying to calm him down. Despite being met with indifference from Midousuji, Ishigaki's friendliness seems to make him immune to rejection when attempting to bond with others. However, Ishigaki is driven to obtain victory for his team and follows Midousuji's plans even if it means leaving exhausted teammates behind and causing emotional and physical pain. Despite using underhanded tactics, Ishigaki respects Midousuji's talent and determination to win, as it produces results, and does his best to support him as an assistant and upperclassman.