Masao Sato, a sensitive and timid boy, sports a shaven head resembling a rice ball, earning him the nickname *Onigiri*. Known as the crybaby of his tight friend group, he startles easily and crumples under minor stressors, yet surprises others with sporadic acts of bravery—usually spurred by his earnest admiration for Ai, a classmate who dotes on him with affectionate mockery, treating him like a pampered pet. His quiet pursuits include hoarding phone cards, cataloging insects, and drafting manga stories inspired by a beloved author. A fixation on cleanliness borders on compulsion, driving him to obsessively tidy both his surroundings and others’ belongings. Friends Shin and Nene playfully taunt him, though Kazama and Bo frequently soften their jabs with gentle reassurance. An alternate reality vignette casts him as Nene’s meek, doting husband, eclipsed by her boldness. Physically slight, he serves as the smallest member of a local defense squad and occasionally relies on diapers, underscoring his fragile demeanor. Even so, flickers of resolve emerge when thoughts of Ai surface. During a hot-springs conflict storyline, he operates in a supporting role, though his precise impact remains undefined.