Sonic the Hedgehog
Chaos is an immortal and ageless, god-like creature composed entirely of concentrated, water-like chaos energy. It was trapped inside the Master Emerald for thousands of years before being released by Doctor Eggman in a plot to conquer the world. Chaos was also the original guardian of the Chaos Emeralds, Chao and the Master Emerald. Chaos eventually absorbed the negative energy of the Chaos Emeralds to attain its final and strongest form, Perfect Chaos.