In the anime, Princess Kakyuu came to Earth to look for the legendary Light of Hope, in the hope it would be able to save the galaxy. In order to protect herself from being discovered by Sailor Galaxia, she hid inside an incense burner, which was found and protected by Chibi Chibi. The Sailor Starlights, disguised as the Three Lights, performed their music to reach out and find their Princess, but she remained in hiding for some time as she tried to secretly discover the location of the Light of Hope.
Princess Kakyuu finally revealed herself in order to save Usagi from the black hole released by Sailor Tin Nyanko, at which time she asked for the help of the Solar System Senshi in searching for the Light of Hope. Sailor Moon wanted to help, but the others were suspicious of the strange Sailor Senshi. Before they could overcome their differences, Sailor Galaxia attacked, and Princess Kakyuu was killed defending the Sailor Starlights.
After Sailor Moon freed Sailor Galaxia, everything was restored, and Princess Kakyuu and her companions returned to Kinmoku.
In the manga, Princess Kakyuu came to Earth to search for Sailor Moon, the legendary soldier she thought could help save the galaxy. Because she was severely wounded in the battle against Shadow Galactica on her home planet, she needed time to heal after arriving on Earth. Chibi Chibi found her lying unconscious in a playground and kept her safe inside an incense burner while she healed her body.
The Sailor Starlights, disguised as the Three Lights, performed their music to reach out and find their Princess. When Seiya drew a connection between the incense burner and the scent of their Princess, the three tried to take the incense burner from Chibi Chibi. Kakyuu then emerged and explained why she had been missing for so long. She then indicated that Chibi Chibi was actually a Sailor Senshi.
After a brief battle with Sailor Tin Nyanko, Princess Kakyuu explained Shadow Galactica to Usagi. She also told Usagi that Sailor Galaxia's final target was Sailor Moon. Usagi decided that she must go fight as a result of this, and Princess Kakyuu guided her to the center of the galaxy, Sagittarius Alpha Star.
It was also revealed in a conversation between Seiya and Usagi that Princess Kakyuu's destined true love was killed by Sailor Galaxia in the battle on their home world.
In the musicals, Princess Kakyuu was played by Sakoto Yoshioka and Ai Toyama.
- Princess Kakyuu was the only other Sailor Senshi besides Sailor Moon who could return Phage to normal.