Bonjiri, one of Sachio's childhood friends, belonged to a group of orphans surviving in the forbidden zone by stealing mechanical parts and trading them to a local mechanic for candy or small sums of money. This group included Sachio, Santa, and Oicho, with Bonjiri participating in their collective struggle for survival within the district's harsh environment.

Seven years after the events of the first season, Bonjiri transitions from youthful theft and operates a diner by the time of the second season. This establishment serves as a practical and symbolic gathering place for the original group—Sachio, Santa, and Oicho—as they navigate their changed lives and relationships.

When Joe returns after a long absence, Bonjiri maintains neutrality toward his reappearance, contrasting with Sachio and Oicho's open hostility. This stance positions Bonjiri as a stabilizing figure within the group dynamic. The diner functions as a backdrop for character interactions and reunions, reflecting a shift from survival-focused existence to Bonjiri's settled community role.