Chaos

Chaos is the final villain in the Pretty Soldier Sailor Stellar series.It is said that it is the source of all evil in the galaxy.

Pretty Soldier Sailor Stellar
In arc 1, Chaos' incarnation in Wiseman, who plans to use the Malefic Black Crystal for world domination. He is defeated by Sailor Stellar and Sailor Moon.

Revolution
In the third and final arc of the series Chaos has reincarnated and has fused with Guardian Cosmos.