Sailor Pluto is the guardian of the Door of Time and Space. She has been guarding it since the Silver Millennium. In the 30th Century, Sailor Pluto was almost like a second mother to Rini, and Rini calls her Luna P or Sailor P. When Rini traveled to the past, she would talk to Sailor Pluto using her Luna Sphere as a communication device. Sailor Pluto was a solitude Soldier, whom could not leave the gates of time as she was it's guardian from negative forces. Later, when the Bureau of Bad Behavior appeared on Earth, she took the identity of Trista Meioh, a Biology Student. Not much is known about Trista, and she tends to have a very closed personality. She will never talk about herself and the only person that really knows her well is Small Lady (Rini). Sailor Pluto joined forces together with Sailor Uranus & Neptune to try and stop the Deafening Silence from ending the world. It also turned out that she held the last Crystal Treasure; The Crystal Ball. When these three treasures were united, they formed the Purity Chalice. Sailor Pluto also gave herself to save Uranus & Neptune by stopping time. In doing so she was punished and banished from this world. However, The true nature of her punishment is still unknown.