Daigaku Kanehira, universally called Kinpira, attends elementary school as a classmate of protagonists Shuhei Amamiya and Kai Ichinose. His overweight physique is repeatedly emphasized in descriptions. Kinpira relentlessly bullies both boys throughout their childhood, employing verbal taunts and physical intimidation as core tactics. He demonstrates consistent aggression and cruelty within school environments, notably pressuring Shuhei into forest piano-related dares during confrontations. No media explores Kinpira’s background, leaving his familial or personal history undisclosed. His character remains static, devoid of development or redemption, functioning solely as an antagonist during the childhood arc. Kinpira vanishes from the narrative after this period, absent from the protagonists' adolescent and adult timelines, and never appears in spin-offs or alternative adaptations. His conflicts primarily underscore socioeconomic disparities among the characters.