Setsuna Meioh, known as Sailor Pluto, guarded the Door of Space and Time. Originating in the Silver Millennium, Queen Serenity assigned her this eternal post under three strict taboos: never leaving her station, never permitting unauthorized time travel, and never disrupting time's flow—the last carrying a death penalty. She carried "the blood of Chronos," marking her divine heritage. She stood witness as Sailor Saturn destroyed the Moon Kingdom. In the 30th century, she guarded the Door for Neo-Queen Serenity, forming a close bond with Princess Chibiusa, who called her "Puu." During the Black Moon Clan's assault, she permitted Sailor Moon and her allies passage through the Time Door to save Crystal Tokyo, violating her taboos. This violation preceded her ultimate sacrifice: stopping time to thwart Prince Demande, breaking the third taboo and paying with her life. Her death freed Chibiusa from Wiseman's control, enabling her transformation into Sailor Chibi Moon. Neo-Queen Serenity reincarnated her in the 20th century as Setsuna Meioh, a university physics student devoid of past memories. During the Infinity arc, an encounter with the Death Busters restored her memories and Sailor Pluto identity. She joined Sailors Uranus and Neptune as an Outer Senshi, later aiding in raising Hotaru Tomoe, Sailor Saturn's reincarnation. Her civilian life involved interests in design and physics, and she developed friendships, particularly with lab colleague Reika Nishimura. In the Dream arc, the Dead Moon Circus initially stripped her transformation abilities, regained only after Hotaru reactivated her Sailor Crystal. She later worked as a nurse at Chibiusa and Hotaru's school during the Stars arc. She battled Shadow Galactica alongside fellow Sailor Guardians, fell to Sailor Galaxia, and was revived when Princess Serenity expelled Chaos from Galaxia. Sailor Pluto commanded spacetime manipulation, generating rifts, teleporting, and enabling time travel via her Garnet Rod. Her ultimate, forbidden ability—halting time entirely—exacted a fatal toll. She wielded the Garnet Orb for defense and possessed the Pluto Crystal, a Talisman used with Uranus's Space Sword and Neptune's Deep Aqua Mirror to summon the Holy Grail. Her appearance featured dark green hair, red eyes, and garnet accents. Her Sailor uniform evolved: the base form had a maroon bow and black choker; Super Sailor Pluto added a garnet heart brooch and translucent shoulder pads; Eternal Sailor Pluto incorporated star motifs, elongated gloves, and layered skirts. As the Door's guardian, she maintained a solitary, duty-bound stoicism, yet showed warmth towards Chibiusa. Post-reincarnation, she displayed a more approachable demeanor, though she deferred to Sailors Uranus and Neptune among the Outer Senshi. She formed a familial bond with Haruka Tenoh, Michiru Kaioh, and Hotaru, living with them later. Musical adaptations explored unrequited feelings for King Endymion, a thread subtly present in manga scenes but not emphasized in the anime or subsequent media.