Uriah "Uri" Peeper is Christopher Peeper's younger brother in the original Japanese version of the series, though the English dub presents them as cousins. Known by his Japanese name Yū Asuka, he lives with the Peeper family: his parents, Professor Frederick "Fred" Peeper and Phoebe Peeper.

Uri takes center stage in the second season when Superbook falls onto a computer keyboard, merging with it to create a virtual portal to biblical times. This accident transports the family's pet dog, Ruffles, into the past. Driven by concern for Ruffles, Uri embarks on a mission to find and retrieve him. He travels through various Old Testament settings accompanied by Gizmo, a full-sized, permanently active robot built by Uri's father. Unlike the first season, Uri's journey focuses primarily on the search for Ruffles rather than direct involvement in the biblical narratives themselves.

Visually, Uri is marked by a shirt featuring the letter "U", a bilingual pun on his Japanese name "Yuu". Throughout his journey, Uri and Gizmo maintain communication with Christopher and Joy in the present, who monitor their progress and provide support via the computer. Gizmo acts as Uri's protector and companion, possessing enhanced capabilities beyond his first-season wind-up toy form.