Sailor Galaxia

&nbsp Sailor Galaxia is an enemy in the final arc of the manga, and Sailor Stars, and she controls the  Sailor Animates. She was originally the strongest Sailor Soldier  in the galaxy, but in fighting  Chaos, she was corrupted. Her goal then became to gather all the "true Star Seeds " from all sailor soldiers to rule the galaxy.

Anime
When fighting Chaos (in flashbacks), she sent out her own Star Seed, her 'light of hope', which took shape as Chibi Chibi. Sailor Galaxia then attempted to seal Chaos within herself. As time passed, Chaos took over her body, and the last part of Sailor Galaxia herself was sealed away within her own body.

She killed Mamoru  on his way to college in America when she captured his plane. Her powers were too strong for all the Sailor Soldiers, except Sailor Moon, who rid her of Chaos.