Her name is Meioh Setsuna, the meaning of which seems to differ greatly among fans. The closest I can find is "instant dark king." Pluto guards the Door of Time-Space and is destined to for eternity. She was told to do so by Queen Serenity, and has several rules she must obey. 1) She cannot leave her post. 2) She must never cross time. 3) She must not stop time. If she breaks the rules, she will die. Still, she is one of the most powerful senshi.
Pluto is mostly a loner, but somehow became a close friend of Chibi-usa, or Small Lady. Pluto has a belt of Time Keys that allow one to travel through time. She also carries a Talisman on her key shaped staff, the Garnet Rod.
