Yū Asuka, renamed Uriah "Uri" Peeper in English adaptations, originates as the younger brother of protagonist Christopher "Chris" Peeper in the Japanese series. Localization adjusts their relationship to cousins in the English dub to align with first-season continuity. Central to the second season, Yū’s role emerges when the Superbook merges with a computer, enabling time travel through its interface. After Chris’s dog Ruffles disappears into biblical times, Yū partners with robot companion Gizmo to traverse Old Testament events, balancing their mission with the series’ educational framework.

Proactive and determined, Yū contrasts with Chris’s initial reluctance, driving dynamic interactions with biblical figures and settings. Their shirt, marked with a "U," incorporates a bilingual visual nod to their Japanese name. Narratively, Yū bridges the computerized Superbook’s technology with historical exploration, emphasizing teamwork and problem-solving. Family ties receive minimal focus, briefly acknowledging his father’s involvement in pivotal episodes and the localized cousin connection to Chris. Yū’s development remains confined to the second season, without expansion through subsequent movies, spin-offs, or other media.