Mistress 9 is the evil messiah of silence. This evil messiah lived inside of Hotaru, as well as Sailor Saturn. Mistress 9's only goal was to get the Sacred Cup and with the help of Master Phaoroh 90, destroy the earth, creating the age of silence. This is the story of the evil that is Mistress 9.

So what is the messiah of silence, you ask? The messiah of silence is the one with the ability to cause the destruction of the world if they come in possesion of the Sacred Cup. Mistress 9 was living within Hotaru. Mistress 9 needed a pure heart crystal of someone of great enerygy to be awakened as the messiah. This unfortunate person was Chibiusa. Hotaru, possessed by the messiah of silence, swallowed the pure heart crystal, and was awakened as Mistress 9.

Mistress 9 killed Kaolinite, who had brought the pure heart crystal to her, and proceeded to instruct Tomoe. Mistress 9 tricked Sailor Moon into giving her the Sacred Cup. Before any damage could be done, Hotaru, who was in fact still alive inside Mistress 9, remembered that she had people that loved her, and Saturn was reborn, destroying Mistress 9. That's really the whole story of Mistress 9.