After the defeat of Sailor Heavy Metal Papillon, Sailor Moon, Princess Kakyuu, Sailor Chibi Chibi, Sailor Chibi Moon, and the Sailor Quartet came upon the Garden Crystal, which was tended by Sailor Phi and Sailor Chi. Immediately the two Star Gardeners attacked and tried to encase the group's Sailor Crystals into their garden. After watching her friends die, and as she was attacked once more, Princess Kakyuu announced her intention to fight as a Senshi, and transformed into Sailor Kakyuu. Kakyuu demanded the return of the Sailor Starlights' Sailor Crystals, then attacked, weakening Sailor Phi enough that Sailor Moon could kill her. However, Sailor Chi then attacked Kakyuu from behind, stabbing her in the back. Kakyuu died in Sailor Moon's arms, her last words an indication of her hope that life would be better after Sailor Galaxia was defeated, and that she herself would be reincarnated with all of her friends. Her Sailor Crystal was then taken by Sailor Galaxia.
Sailor Kakyuu is the only Senshi whose Senshi form is not named after a planet, but her own name.
- Kinmoku Star Power, Make Up - The phrase Princess Kakyuu used to transform into Sailor Kakyuu.
- Starlight Royal Straight Flush - Calling on the power of the Sailor Starlights, Kakyuu summoned cards that were thrown at enemies.
- Kinmoku Fusion Tempest - Kakyuu summoned up a blizzard of Osmanthus olive blossoms to attack enemies. It was similar to Sailor Jupiter's Flower Hurricane, but presumably stronger.