Chaos in not actually a villain but is put here because you have to fight him throughout the game. Chaos is a creature from Sonic Adventure or Sonic Adventure DX Director's Cut. He is a liquid-life form that was trapped in the Master Emerald but was released by Eggman. Whenever he gains a chaos emerald he changes shape to look bigger and badder. Before he was trapped in the master emerald he destroyed everything on the planet and then Tikal trapped him away, for what was supposed to be, forever. When he was released by Eggman he acted as Eggman's minion but then betrayed him and became Perfect Chaos. He then could only be stopped by Super Sonic to take all of the anger out of him. Here are his forms.






Chaos 0






Chaos 1





Chaos 2









Chaos 3 Never Seen









Chaos 4









Chaos 5 Never Seen









Chaos 6











Perfect Chaos! (all seven chaos emeralds)