Okiku is a zashiki warashi, a household spirit from Japanese folklore known for bringing good luck and protection to homes. She inhabits the protagonist's residence, acting as a guardian spirit who manipulates household objects and influences the domestic environment. Her presence highlights themes of tradition and cultural heritage within a contemporary setting.

She appears as a young girl with long, flowing black hair, dressed in a traditional kimono and obi, matching typical depictions of her kind. Okiku's personality blends mischievousness with underlying kindness; she plays pranks on the household residents but remains fiercely protective of the home and its inhabitants. This duality makes her a benevolent figure who intervenes against malevolent supernatural threats.

A notable trait is her habit of counting things, expressed by the phrase "I have a habit of counting things." This behavior subtly evokes the classic Japanese ghost story "Bancho Sarayashiki," featuring the tragic servant Okiku who becomes a plate-counting ghost near a well, alluding to themes of injustice and spectral persistence in folklore.

Her narrative role centers on comedic interactions intertwined with protective duties, exploring supernatural cohabitation in modern life. She appears in episodes 6, 7, 8, and 11, where her actions advance subplots involving household dynamics and supernatural conflicts. Her presence reinforces the zashiki warashi folklore motif that respectful treatment of such spirits ensures household prosperity and wards off misfortune.