Ruri emerges from a sealed jar found beneath the floorboards of a rented room, identifying herself as a snow fairy (yuki-onna). Her supernatural origins are tied directly to this mysterious jar, which produced her when its seal was broken.

She possesses long blond hair, frequently styled in braids or ponytails and reaching waist length or longer. Heterochromia marks her most distinctive feature, giving her one blue or green eye and one red eye. She is depicted in various attire including aprons, dresses, kimonos, skirts, T-shirts, jackets, and hair ribbons.

Her personality blends naivety with friendliness. She engages in domestic activities like cooking and shows an interest in gaming. Despite this seemingly gentle nature, her background involves psychological trauma and a split personality.

Her narrative centers on her sudden emergence from the jar and subsequent cohabitation with the protagonist, Hiroshi. This relationship defines her role as she adapts to human life while her supernatural origins remain integral.