Tomoe Soichi was Hotaru's father and was the owner and principle of a private school called the Mugen Gakeun, which means "Infinity High School". His daughter Hotaru, along with Haruka and Michiru, attends this school. His wife had passed away years before, so Hotaru is the only family he has left. And since Hotaru is his only child, he will do anything for her.
One day, during an experiment in his laboratory, there was an explosion and everyone who was in the lab died, including his daughter. But he did not die. Thus, the Germatos Daimon said he would bring Hotaru back to life if he could infest Tomoe and have him become his vessel and have Hotaru be the vessel of Mistress 9. Tomoe agreed and since then has been controlled by the spirit of the Daimon. In his secret laboratory, he would create greyish-purple eggs called Daimon Eggs. At first, these eggs would find a target, someone who housed a pure heart crystal, and would infest a specific object. This would create a monster with traits of that object in consumed. Later, Professor Tomoe would create the daimon from the Daimon Egg first, and then give it to one of the Witches 5 to use in case there was an interference with the Sailor Soldiers. When Sailor Uranus and Neptune tried to enter into his laboratory, the Germatos Daimon left Tomoe's body to stop them and Tomoe was freed. The Germatos Daimon was later destroyed by Sailor Uranus and Neptune when they used their talismans to attack.
Kaolinite
Kaolinite was the first apprenitce of Professor Tomoe who was also infested by a daimon and who tried to search for the talismans. She used too many of Tomoe's eggs which made him angry. Then she found Usagi as the next target and told the Professor that she had and extremley pure heart and it might be a talisman. Kaolinite discovered that it was Usagi's birthday and that she wanted glass slippers from Mamoru. So, she put a Daimon Egg inside a pair. The Daimon appeared when Usagi tried them on. It knocked away her transformation brooch and extracted her pure heart. Sailor Neptune and Uranus watched on and realized that Usagi's heart crystal had a remarkable shine to it and they thought it might be a talisman. Tuxedo Mask saved Usagi and escaped with her. Kaolinite then stole Usagi's transformatin brooch. Kaolinite and her daimon later caught Usagi and Tuxedo Mask and the daimon froze Tuxedo Mask in glass and took him hostage at the Tokyo Tower. At the Tokyo Tower, the Inner Soldiers saved Usagi and Tuxedo Mask. Kaolinite was supposedly killed when the Inners used "Sailor Planet Attack" on her and Uranus knocked her off the tower using her "World Shaking". But actually, she was not killed and was later seen as a lab assistant to Professor Tomoe who would torment Hotaru. She was officially killed when Mistress 9 killed her because she was of no use anymore.
Mistress 9 was the daimon that used Hotaru, Professor Tomoe's daughter, as her vessel. When Professor Tomoe agreed to let the Daimon Master use him as his vessel so he could save Hotaru from death, the Daimon Master brought Hotaru back to life by infesting her with the Messiah of Silence, which now became known as Mistress 9. After Mistress 9 was brought out by swallowing Sailor Chibi-Moon's pure heart crystal, she killed Kaolinite because she was of no use to their mission. Mistress 9 convinced Sailor Moon to give her the Holy Grail by transforming into Hotaru and beggin for it. Sailor Moon thought that if she gave the Holy Grail to her, Hotaru would be saved. So she did. But instead, Mistress 9 appeared again, destroyed the Holy Grail, and called forth her great master, Pharoah 90. Pharoah 90 was a large entity that looked like a black hole. After Pharoah 90's arrival, it would engulf the whole planet in silence and cause the end of the world. Mistress 9 was killed when Hotaru, still living in Mistress 9's spirit, gathered up her powers and destroyed her. After that, Hotaru became Sailor Saturn and returned Chibi-Usa's heart crystal to her.
