Kakyuu is the princess of the SailorStarlights. The Starlights come to Earth in search of her.
Princess Kakyuu makes her first actual appearance in episode 193, floating in the air and holding Usagi in her arms. Usagi and ChibiChibi were sucked into a black hole that Tin Nyanko created, and ChibiChibi called Kakyuu using her Chalice/ incence burner, where Kakyuu had hidden herself. In episode 194, her identity as the Starlights' princess is revealed. ChibiChibi is the one who helped Kakyuu find Earth, using the chalice and caring for it. After arriving, Kakyuu asks the Sailor Senshi to help her stop Galaxia, but Uranus and Neptune are angered by her request so Kakyuu leaves with the Starlights.
In episode 195, Galaxia takes her star seed, and she subsequently dies. However, she comes back to life at the end of episode 200 after Sailormoon heals Galaxia. Then Kakyuu and the Starlights leave Earth to start a new life.
In the Manga she transforms into Princess Fireball becoming a Sailor Senshi. Kakyuu means Fireball and comes from Kinmoku. "Kinmokusei" is a Japanese pun on the word for "sweet olive", which explains her scent and why she became an incense burner.
