Not much is known about Princess Kakyuu. She comes from a distant planet that was destroyed by Galaxia. Her and her protectors(The Starlights) escaped and came to Earth. The Starlights and Kakyuu got seperated and now the Starlights are looking for her. This is why they came to Earth in the form of guys, believeing it would be the easiest way to find her. It was Chibi Chibi who found her in a censer and released her. Kakyuu was killed by Galaxia in 2 episodes after she was found. She only appeared in the Sailor Stars season.

In the manga, Princess Kakyuu is also a Sailor Soldier who fights with Usagi.

Kakyuu watches the Starlights get killed and then she is killed by Sailor Chi. (Chi did not appear in the Anime)