Many years ago a war called the Sailor Wars started. An evil force known as Chaos had been going through the galaxy causing death and destruction, but one Sailor Soldier chose to stand up to that force--That Soldier being the senshi of the galaxy, Sailor Galaxia.
She was a great soldier, one of the most powerful, but she was also arrogant. She thought she was the only one who could defeat Chaos and she did so by thrusting her sword into the heart of evil force sealing it inside of herself. But that was a mistake to do because Chaos then began to slowly take over her body.
She
knew she had to do something before she lost complete control of herself.
So she sent her 'light of hope' away to some where far away.
After that Galaxia started her evil venture to take over the galaxy under the influence of Chaos. This was the start of the Sailor Wars -- Soldier against soldier fighting for the fate of the galaxy. Galaxia went from planet to planet destroying those who opposed and gaining minions on her way -- The animamates (Aluminum Seiren, Tin Nyanko, Lead Crow, and Iron Mouse. The planet Kinmoku was one of her stops, but Kakyuu and the Sailor Starlights had fled before she could do anything about them. She conquered around 80% of the galaxy before coming upon earth.
On Earth Galaxia set up Galaxy TV Studios which served as a headquarters while the Sailor Animamates went out in search of true star seeds. Galaxia was the president of the TV studio in a sense. In the studio building itself there was a secret elevator that traveled to another dimension of sorts and that is where Galaxia spent most of her time. Whenever she wished to speak to the Sailor Animamates she called them there. She also speaked to them (or at least Iron Mouse) through the use of a special black telephone.
She did not take failure lightly and Sailor Iron Mouse was one of the first
to feel her wrath (after hanging up on her of course). Later on Tin Nyanko
suggested to Galaxia that she kill Aluminum Seiren for her repeated failures,
and she did. However in the end Tin Nyanko also felt Galaxia's wrath --
Eternal Sailor Moon healed her part way and Nyanko was fighting with herself
over what she should be doing. Galaxia merely took away her bracelets and
the cat-Animamate faded away.
When Eternal Sailor Moon and the other Sailor Soldiers finally figured
out that Galaxy TV was the place they needed to go they all went there to
face her. Venus, Mercury, Mars, and Jupiter were the first to be killed
after they jumped in the way of a blast meant for the Sailor Starlights.
Later on when Uranus, Neptune, Pluto, and Saturn faced her, Uranus and Neptune
joined up with Galaxia to try and betray her from the inside -- they ended
up killing Pluto and Saturn in the process. Later they turned on
Galaxia
but were unable to hurt her, she took away their bracelets and they died.
Sailor Moon was finally forced to fight Galaxia and a vicious battle took place, Chaos eventually took over Galaxia's whole body turning her suit and skin a dark color. Sailor Moon did not want to fight and was determined to reach the good in Galaxia. In the end she was able to get through and free the galaxy soldier from the evil hold.
Galaxia first appeared in episode 167, though she was not seen at that time. But she was the one who freed Nehellenia from the seal Sailor Moon put her in.
