First year Yuika is an assistant librarian with Keiki. One quarter Caucasian she has blonde hair and blue eyes, and is initially shy and stand-offish, but warms up to Keiki's persistent attempts to get to know her. She's secretly a sadist who wishes to make Keiki her slave. She found out about Sayuki's fetish the first time they met and has been fighting to "protect" Keiki from "the Witch's" clutches.