Kakyuu is the princess of Kinmoku, a fictional planet outside of the solar system. She is said to smell like the flowers of the Fragrant Olives, which are a recurring motif in her character design. The name of her planet is a pun on the name of these fragrant blossoms, which are called kinmokusei in Japanese--the suffix sei, when added to Kinmoku, means "planet" or "star." When Kakyuu first introduces herself, she calls her specific kingdom Tankei, a homonym of another word which also means the Fragrant Olives shrub.

Kinmoku is also the home of the Sailor Starlights, who are Kakyuu's protectors and spend much of the story searching for her. The details of their collective story vary between the manga and the anime.