Civilian
Setsuna is depicted as a young woman with long, knee-length dark green hair, partially styled in a high bun while the remainder flows freely. She has striking red eyes, though some variations portray her with purple eyes and lighter skin. Compared to the other Sailor Guardians, her skin tone is slightly darker, adding to her distinct appearance.

Sailor Pluto
In her Sailor Pluto form, her uniform consists of a white sleeveless leotard paired with a maroon chest bow adorned with a red circular brooch. She wears a stripeless black sailor collar, a golden tiara featuring a garnet-red gem, and thick, arrow-shaped red earrings. Her choker is black with a red accent, and her gloves reach her elbows with black padding. She wears a black skirt with a maroon bow at the back, and her footwear consists of knee-high black heeled boots with white triangular accents.

Super Sailor Pluto
When she transforms into Super Sailor Pluto, her choker features a star with a bright red gem in the center. Her sailor collar now has a single white stripe, and her brooch takes on a heart shape. Her outfit includes shoulder pads like the other Sailor Guardians, though hers are wing-shaped and translucent at the edges. The ribbons on her back bow are larger and extend further down her back.

Eternal Sailor Pluto
Eternal Sailor Pluto’s uniform features the most significant transformations. Her tiara’s gem is now star-shaped, and her earrings are black stars hanging from gold studs. She wears a V-shaped choker with a yellow star at the center. Her sailor collar has a single gold stripe, and her brooch is now shaped like a star. Her shoulder pads are replaced by short, light black bubble-like sleeves with black bands at the ends, and her gloves reach just below these sleeves. The skirt is layered, with a black top layer and a light black bottom layer, connected to her leotard by a black and light-black belt adorned with a yellow star at the center. Her back bow, similar in style to her original form, is now light black, with slim black ribbons extending to her knees. Her knee-high boots feature black V-shaped borders with a yellow star in the center.

Princess Pluto
As Princess Pluto, she dons a regal black dress with white draped fabric and four straps decorated with gold accents. Her accessories include a gold pendant and black high-heeled shoes with straps.

As a university student, Setsuna Meiou is older than the other Sailor Guardians, who are still in middle or high school. Despite being the eldest, she doesn’t take on an official leadership role within the group. Even among the Outer Guardians, Setsuna often defers to Sailor Uranus and Sailor Neptune for direction. She shares a unique and close bond with Chibiusa, acting as a supportive figure in her life.

Background
Sailor Pluto, the princess of the planet Pluto and daughter of Chronos, the God of Time, was entrusted with guarding the Door of Space and Time from a young age. Queen Serenity assigned her this critical task, setting three absolute taboos she was forbidden to break: she must never abandon her post, never permit unauthorized time travel, and never disrupt the natural flow of time, with the last rule carrying a life-ending consequence if broken. However, when the Silver Millennium was attacked by the Dark Kingdom, Sailor Pluto was drawn to join Sailor Uranus and Sailor Neptune, as their sacred talismans—the Garnet Orb, the Space Sword, and the Deep Aqua Mirror—resonated together, awakening Sailor Saturn. Pluto could only watch as Sailor Saturn unleashed her Silence Glaive, erasing the remnants of the Moon Kingdom.

After being reborn, Sailor Pluto resumed her role as the guardian of the Space-Time Door. During the second Silver Millennium, she met Princess Usagi Small Lady Serenity, who had wandered down a forbidden hall in the Crystal Palace and found the Door of Space-Time. The two formed a close bond, with Pluto encouraging Chibiusa and reassuring her that she would grow to be strong like her mother. Later, when Crystal Tokyo fell under attack from the Black Moon, Chibiusa took one of Sailor Pluto’s Space-Time Keys and journeyed to the 20th century.

Black Moon Arc
When Sailor Moon, Sailor Venus, Tuxedo Mask, and Chibiusa approach the Time Gate, Sailor Pluto initially tries to prevent them from using it. However, upon recognizing Chibiusa, she allows them to travel to the 30th century. When Prince Demande attempts to merge the Silver Crystals of past and future to bring about destruction, Sailor Pluto takes the drastic measure of stopping time to save everyone, fully aware it will cost her life. Her sacrifice frees Chibiusa from Wiseman’s control, allowing her to become Sailor Chibi Moon.

Infinity Arc
In this arc, Setsuna reappears as a university student studying physics at K.O. University and works in a research lab, befriending Reika Nishimura, who works in a nearby lab. Reborn by Neo-Queen Serenity’s power, Setsuna has no memories of her previous life as Sailor Pluto. However, she and her professor notice strange distortions around the Sankakusu area. Setsuna later falls victim to Tellu’s Tellun plant, which leaves her weakened and calls out for help. A powerful inner voice awakens her latent powers, and the symbol of Pluto appears on her forehead, triggering the reawakening of Sailor Uranus and Sailor Neptune. Now fully transformed back into Sailor Pluto with her memories intact, she joins the other Outer Sailor Guardians to confront the Death Busters and prevent Sailor Saturn’s awakening. Following the events at Mugen Academy, Setsuna, Michiru, and Haruka begin raising baby Hotaru together.

Dream Arc
At the observatory, Setsuna senses a dark presence from the Dead Moon Circus during a solar eclipse. Although she initially struggles to transform, Hotaru later projects an image of the solar system, revealing the eclipse’s ominous effect. While the Outer Senshi initially feel their help might not be needed due to their inability to transform, Hotaru reawakens as Sailor Saturn and bestows upon them their Sailor Crystals, enabling them to transform and join the battle.

Stars Arc
After the defeat of the Dead Moon Circus, Setsuna becomes part of the everyday lives of Usagi and the others, taking up a position as a nurse at Juban Public Elementary School, where Hotaru and Chibiusa study. As Shadow Galactica’s invasion intensifies, Setsuna, along with Haruka and Michiru, travels to their castles to raise a protective shield around the Solar System with their Sailor Power Guardians. At Charon Castle, Sailor Pluto is greeted by Guardian Pluto, and they discuss their findings. As they begin raising the shield, they realize their enemies are approaching from the center of the Milky Way. Sailor Galaxia arrives, ultimately defeating Guardian Pluto and Eternal Sailor Pluto. Hotaru senses the danger and arrives to help, but both she and Guardian Saturn are also killed.

Galaxia, wielding her Galactica Bracelets, later resurrects Pluto along with the Inner and Outer Senshi, sending them to confront Eternal Sailor Moon. They are defeated once more, but eventually, they are all properly revived within the Galaxy Cauldron.

Phrases:

• Pluto Planet Power, Make Up
• Pluto Crystal Power, Make Up

Weapons and Items:

• Space-Time Key
• Garnet Orb
• Garnet Rod
• Pluto Crystal

Attacks:

• Dead Scream
• Time Stop
• Chronos Typhoon
• Garnet Ball
• Dark Dome Close
• Sailor Planet Power Meditation
• Galactica Cannon
• Galactica Planet Attack

Setsuna: Though her name is written in hiragana without an inherent meaning, the name “Setsuna” can be interpreted as “moment,” linking to her control over time, or as “sorrow,” reflecting her often solemn role.

Meiou:  The kanji for “Mei” (冥) translates to “dark,” while “ou” (王) means “king.” This mirrors the Japanese name for the planet Pluto, Meiohsei (冥王星), or “Nether King Star,” referencing Pluto, the Roman god of the underworld.

Together, her name could be interpreted as “Momentary Dark King” or “Sorrowful Dark King,” alluding to both her powers and her character’s themes.