Princess Kaiyuu is from the planet Kinmoku. She is a Princess more like how Bunny and Jasmine are princesses. She came to Earth in search of her sister Kakyuu but she took the form of a kitten to disguise herself so Galaxia would know who she was. Her sister Kakyuu was hiding inside of an Urn Chibi-Chibi mysteriously found. The planet Kinmoku is in another galaxy and planet Kinmoku was attacked in the Sailor Wars by Chaos / Evil Sailor Galaxia. Princess Kaiyuu and Kakyuu both fled to Earth where she felt she would be safe. We don't see these princesses until later on in the story when Jasmine and Bunny are in danger of having their star seeds taken from them. Princess Kaiyuu has a Senshi form but she never transforms in the story. Her star seed is taken before she even has a chance to do so. “Starlights Royal Straight Flush Whirlwind!!” and “Kinmoku Fusion Tempest Fire!”