Naturally Sailor Kakyuu is Princess Kakyuu (Fireball/Kinmoku). I think she goes by Princess Kinomoku, but people call her so many names I just thought to mention all of them. I will refer to her as Kakyuu though because this is manily focusing on her Sailor form.
She was the First Order Princess of the Red Ceres Kingdom on the planet Kinmoku. On her home planet, her lover was killed by Chaos, and she was almost killed while batteling Galaxia. But her starseed was saved in an incense burner, and protected by Chibi Chibi. They didn't need for Chaos to get the thrid Starseed they needed. The Starlights knew she was alive somewhere. I'm guessing that they were her protectors. They followed her scent to earth, and turned themselves into men. They did this for many reasons. One, men can smell better, two it is less questionable for a man to ask where a girl is, as a male idol music group they could attract girls, and (like in the Anime) they could send messages through their songs in hopes of finding her.
They finally do find her, but Galaxia comes and kills her. She dies in Eternal Sailor Moon arms.
*In the manga, she could grow wings, and she is the one who lead Moon to the Cauldron. Galaxia wasn't even the one who killed her. The starlights did still come to look for her and found her, but they were killed before her by Sailor Chi and Phi. The Princess was teased so much about their deaths that she transformed into Sailor Kakyuu. She distracted Phi so that Eternal Sailor Moon could kill her, but Chi killed Kakyuu for the loss of her sister. This is where the Asteroid Senshi showed up to help Moon kill Chi.
~Back to Kakyuu's Shrine~