Kouichi Minato is a professional photographer and a supporting character. He attended high school with both Haru Nonaka and Shinako Morinome in the same class before Haru dropped out. Minato possesses an average build and height, sporting a goatee and sidelined hair. He often carries himself with a relaxed posture that suggests laziness, masking his true diligence.

During high school, Minato developed romantic feelings for Haru that endured into adulthood. He later found employment at a photography studio, starting as an assistant before gradually securing his own assignments. His connection to Haru reignites when they meet at Rikuo Uozumi's workplace, where Minato confesses his persistent affection.

Haru rejects Minato's romantic pursuit. Following this personal setback, he achieves professional advancement, moving from assistant roles to independent photography work. Despite the rejection, he remains present in Haru's life and interacts with Rikuo. In one conversation, Minato cautions Rikuo about the potential consequences of indecision regarding Haru, implicitly referencing his own experience of unrequited love.

Minato's arc concludes with a sense of resignation concerning his feelings for Haru, paired with ongoing dedication to his photography career. He embodies a mature, somewhat weary demeanor, shaped by unresolved past emotions and his observations of the central relationships around him.