Mudo Kirihara is a boy in Sunao Moriyama's junior high school class. He develops an early fascination with the creature Potemayo soon after she appears near Sunao. Despite this persistent interest, he never manages to touch or pet Potemayo due to her protective nature around Sunao.

A significant incident occurs during his second year of junior high on Valentine's Day when he mistakenly gives chocolate to classmate Nene Kasugano. This error leads to his temporary servitude to Nene. He finds Nene visually appealing only when she remains completely silent.

Mudo participates in the school's cheerleading club, wearing the full female cheerleader uniform during official activities and events. He maintains a close friendship with classmate Kaoru Hatsushiba, who openly expresses attraction toward him and actively supports his attempts to interact with Potemayo.

A recurring pattern involves Mudo suffering severe physical injuries, frequently as a direct result of encounters with the destructive creature Guchuko.