Sailor Galaxia appears as Sailor Moon's strongest opponent in the manga Stars and its anime counterpart, Sailor Stars. She is the self-proclaimed "Golden Queen of Shadow Galactica," commanding the Sailor Animamates directly. Her ultimate goal is to gather all the Sailor Crystals in the universe to rule it unchallenged.
In the anime, Sailor Galaxia was once the legendary strongest Sailor Senshi in the universe. The Sailor Wars saw her battling those who threatened love and justice. Eventually, she sealed Chaos, the source of all malice, within herself to save the cosmos. However, Chaos grew stronger over time, and realizing the danger she posed, Galaxia expelled her star seed into the Milky Way galaxy. This was her final act of free will before becoming completely controlled by Chaos. Now under Chaos' influence, Sailor Galaxia aimed to steal all star seeds to dominate the universe. In the end, Sailor Moon gave Galaxia the strength to expel Chaos from her body, restoring balance by returning darkness to where it belongs alongside the Light of Hope. Galaxia then departed, tasked with returning all the star seeds to their rightful places.
In the manga, Sailor Galaxia was born alone on a small planet she considered "trash." Wandering aimlessly until her powers awakened, she felt a lack of purpose in life. Even being a Sailor Senshi wasn't enough for her; she craved more, thinking it was power. Leaving her planet, she searched for a new home. During her travels, she encountered a bar where someone mentioned the "holy land" she sought. That person was Chaos, disguised as Wiseman, who revealed the Galaxy Cauldron to her. To gain control of the Galaxy Cauldron, Galaxia needed to collect all the Sailor Crystals of the galaxy's Sailor Soldiers. Combining these powers with Sailor Moon's would allow her to kill Chaos and rule the galaxy. Thus, she created Shadow Galactica and began conquering planets, turning them into wastelands and stealing the star seeds of their guardian Sailor Soldiers. By stealing star seeds, she could revive dead bodies and use them as puppets, including the solar system's Sailor Soldiers. Her first conquest on Earth involved stealing Mamoru's golden star seed right in front of Usagi, followed by targeting each Sailor Soldier until only Sailor Moon, Chibichibi, and the Sailor Quartet remained. At the Galaxy Cauldron, Galaxia fought them until Chaos tried to kill her by blasting her off a cliff. Sailor Moon saved her from falling into the cauldron, and Galaxia realized that what she truly wanted was love, not power. By accepting Sailor Moon's offer of friendship, the bracelets that sustained Galaxia shattered, and she died with a smile on her face.
