The 25 Years of Sonic the Hedgehog

Chaos

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 Dr. Eggman in a plot to conquer the world. Chaos was also the original guardian of the chaos emeralds, chao, and the Master Emerald. In Sonic Adventure, Chaos absorbed the negative energy of the Chaos Emeralds to attain its final and strongest form, Perfect Chaos.

Chaos was originally a normal Chao, but prolonged exposure to the energy of the Master Emerald caused it to mutate into a strange water-like creature. It used its new powers to guarantee clean water around the altar of the Master Emerald, and to protect its fellow chao. However, about 4,000 years ago, the leader of the Echidna tribe, Pachacamac, attempted to steal the emeralds for use against his enemies. Tikal, his daughter, resented this idea, worrying that it would upset Chaos and it would bring wrath to them, but Pachacamac did not want to hear it. His warriors stormed the shrine, where the emeralds reside. Many chao were injured in the process, as was Tikal herself. Chaos, in a fit of rage, absorbed the negative power of the seven chaos emeralds, and transformed into Perfect Chaos. As a result, it became a massive water creature. Floods destroyed the civilization, and Chaos avenged its chao bretheren. In order to prevent Chaos from destroying the world, Tikal linked her consciousness with Chaos' via a prayer, and sealed them both into the Master Emerald. It is probably from this point in history that the emeralds were called the "Chaos Emeralds".

Chaos lay dormant in the Master Emerald for thousands of years until Dr. Robotnik, having read ancient tablets describing the fall of the Echidnas and chaos, released it by shattering the Master Emerald. Chaos swore to follow Doctor Eggman as it knew that he could get the chaos emeralds back for it. Sonic eventually encountered Chaos as it was attacking a building and several Police officers, and easily defeated it. Because of its appearance, Sonic initially referred to it as "big drip."

Eventually, Robotnik's plans, as always, fell through the hands of Sonic and his friends. Chaos eventually abandoned Dr. Robotnik, destroying his Egg Carrier in the process, and collected the chaos emeralds for itself. Once they were in its possession, it absorbed the negative powers of the emeralds once again and transformed into Perfect Chaos to destroy Station Square in a rage. Having only taken the negative energy, Chaos discarded the remnants of the chaos emeralds. This proved to be the means to Perfect Chaos's downfall as Sonic absorbed the positive energy of the chaos emeralds and transformed into Super Sonic, eventually defeating it and in the process, it's evil mindset was returned to its regular states do turned back into Chaos 0. Tikal then approached Chaos, and together they disappeared in a flash of light.