Hiyori’s father, a bespectacled man with facial hair, crafts a humanoid robot mimicking Hiyori’s late grandmother to soothe her sorrow after the grandmother’s passing. The robot features dentures and a likeness of the elderly woman, its mobility adjustable—capable of shifting from a pace slower than a rhinoceros beetle to speeds surpassing a bullet train. His creation anchors the narrative, emphasizing its emotional resonance for Hiyori rather than delving into his personal history or future trajectory.