Oyuki is the queen of Neptune, which in the series is a frozen, snowy planet populated entirely by women, as most of the men have to go off-planet to find work. As a child she used to hang out with Lum, Ran, and Benten when they were all in grade school. She is clearly patterned after the yuki-onna (literally "snow woman") of Japanese folklore. As such, she has the power to control and create ice, snow, and extreme cold. Typically dressed in a long, elegant kimono, Oyuki is soft-spoken, regal in demeanor and very slow to show anger. However, once roused to actually display her abilities she proves to be the most powerful character in the series. Because of the wrath she displays when angered, Oyuki is the only person in the entire galaxy that Ran genuinely fears.