The Chaos Emeralds are seven ancient relics of great power from the Sonic the Hedgehog series. The Chaos Emeralds have mystical properties and abilities, and the holder of them all can use them for a large variety of things, such as initiating a super transformation, powering machines, and warping time and space. Due to the immense powers they possess, they are usually the target of villains, who desire them to fuel their own evil ambitions, and of heroes, who want to keep them away from the villains and use them for good. After the conclusion of a story, the emeralds tend to scatter themselves, and as such characters often collect them throughout the games. While they were more like "bonus" items in the early games of the series, the Chaos Emeralds became necessary plot devices in Sonic Adventure, and that trend has continued throughout the later 3D games.