Professor Soichi Tomoe, a renowned scientist, took his daughter, Hotaru, with him to his lab. There was huge explosion and Hotaru was killed. The daimon Germatou appeared to Professor Tomoe, and Tomoe begged for his daughter's life. The daimon possessed him, and Mistress 9 entered his daughter's body, where she remained dormant for many years. In this was was Hotaru's life returned.
In preparation for the Silence, Mistress Nine slowly took over Hotaru's body causing Hotaru to become the Messiah of Silence. By swallowing Chibi-Usa's heart crystal, Hotaru completely transformed into Mistress Nine, the Messiah of Silence.
Mistress Nine established a base in the Mugen Academy where she awaited the coming of the Sailor Senshi and the Sacred Cup (Holy Grail). When they arrived, she grabbed SailorMoon and constructed a daimon barrier to prevent the other senshi from coming near her. SailorNeptune and SailorUranus eventually breached the barrier, with the help of SailorPluto, with the intent of killing Mistress Nine. Mistress Nine disguised herself as Hotaru and sent the daimon Germatou to dispose of the two senshi while she retrieved the Sacred Cup from SailorMoon.
Mistress Nine made one slip-up. She called SailorMoon Tsukino Usagi, and SailorMoon realized it was not Hotaru. Mistress Nine shed her disguise as Uranus and Neptune entered, having survived the attack by Germatou. The two outer senshi attacked Mistress Nine, but SailorMoon took the blow, desperately trying to save Hotaru, whom she believed still existed in Mistress Nine.
Quickly, Mistress Nine, wrapped the two outer senshi up in her hair. She used them as trade offer for the sacred cup by threatening to kill them if SailorMoon didn't give her the Sacred Cup. Professor Tomoe, having been freed of the daimon's influence, interrupted, looking to save his daughter. Hotaru's spirit took over and Mistress Nine struggled to regain control. Pleading that the Sacred Cup was the only way for Hotaru to be free, Mistress Nine finally succeeded in getting the cup from SailorMoon.
She destroyed the Sacred Cup, brought Pharaoh Ninety to Earth, and began the destruction of the planet. However, Hotaru, buried deep inside Mistress Nine, remembered the ones who loved her and completely destroyed Mistress Nine. She transformed into Sailor Saturn, and, with the help of SailorMoon, she destroyed Pharaoh Ninety. As the Sacrificing Soldier, she too was destroyed, but she was then reborn, and the baby was given to Professor Tomoe.
