Once she has been the most powerful Sailor Senshi in the universe. After a long fight against Chaos she decides to protect the universe alone and seals Chaos within her body. She pierces her sword into the ground of some distant planet, a gap opens  and the sword  turns into stone. Form that day on the Galaxy has a peaceful place with no Chaos anywhere but in SailorGalaxia's heart. She has to fight against its dark powers every single moment and finally Chaos corrupts her. Two bracelets appear round her wrists as sings of her enslavement  but also as powerful weapons. She has no choice but to let her own star seed go, she sends it away to find a save place. From now on  she starts to collect all star seeds in the universe and she is very successful. She keeps them in a special place, in her very own dimension where the remains of her good side, a lonely, beautiful Galaxia stands on a high rock surrounded by star seed flowers with their petals closed and most of the seeds trapped inside...
Galaxia gathers other Senshi around her, senshi whose star seeds she also has collected but who were too weak to die but choose to be her servants instead: The Anima-mates. She gives them bracelets as weapons so that they can collect star seeds for her. She also controls them with the help of the bracelets. They know that she can take them back any time she wants and without their bracelets they will vanish.  After Galaxia has destroyed each single planet she comes to earth. She frees Neherenia knowing that all Sailor Senshi of this planet will have to fight together in order to defeat her. By this means Galaxia ensures that Sailorsaturn has to be awakened again and her star seed develops its full powers. Galaxia doesn't fear any of the Senshi not even Sailorsaturn. She kills, Tuxedo Kamen, Princess Kakyuu and the  Inner Senshi with the power of  her bracelets. Although Uranus and Neptune attack her together they are no match for her. Galaxia is fooled by their "betrayal" and takes their star seeds in return für two pair of bracelets. Uranus and Neptune kill Pluto and Saturn, attack Sailormoon and the StarLights but finally they try to blast Galaxia with her own weapons. They fail and Galaxia kills them.  When the StarLights fight together they can hurt her  a little bit but the cut in her arm heals at once. She tells them that she is the legendary Sailor Senshi and summons her sword. This is her greatest weapon. Galaxia has already started to destroy Tokyo with her black lightning. People lie unconscious in the streets and their star seeds float above them. With a single stroke of the black sword she destroys the TV station that she has used as secret portal to her dimension. During her fight against Sailormoon Chaos takes over her body completely. Her golden fuku turns black and she gets bat like  wings. But no matter how hard she try to torture and kill Sailormoon she is not able to withstand the power of Sailormoons heart and the Silver Crystal. Her sword breaks.   The good Galaxia is still alive and sees Sailormoon's light of hope. When Sailormoon takes Galaxia's hand Chaos has lost.  Chaos leaves her
body. She turns into the beautiful woman she has been before and all star seeds are free. Galaxia is worried because Chaos has not vanished but returned into everyone's heart but Sailormoon can convince her that it is no longer a real danger. Finally Galaxia leads the star seeds back to where they belong and disappears in a flash of light.