Chaos (カオス Kaosu), also referred to as the god of destruction (破壊神 Hakai-shin), is a character that appears in the Sonic the Hedgehog series. It is an immortal mutant Chao and a godlike figure who serves as the guardian god of the Chao and their friends. Its body is composed entirely of concentrated energy, and it has the ability to change form and evolve with each Chaos Emerald that it absorbs. The first known guardian of the Chaos Emeralds, Chaos watched over a Chao colony in ancient times. However, 3,000 years ago, an attack from the Knuckles Clan led to it being consumed by a fury that threatened to destroy the world. However, it was sealed in the Master Emerald before it could succeed. In the present day, it was released by Dr. Eggman for a plot to conquer the world. Despite initial cooperation however, Chaos eventually revolted and tried to destroy the world. Fortunately, it was soon calmed by Sonic and departed for places unknown in peace. Since then, Chaos has only re-emerged in times of great crisis.