Chaos is the main evil in the games Warhammer
and Warhammer 40.000. Chaos consists of four gods. These are knows as The Chaos Gods, The Dark Gods or The Ruinous Powers. Each god tries to become the dominant Chaos Power, but, as is the nature of Chaos, none can ever succeed. The four gods are: Khorne
, the Blood God, Nurgle
, the Lord of Decay, Slaanesh, the Prince of Excess and Tzeentch, the Lord of Change. Many follow one particular god and wage war against the followers of the other gods, but many more worship Chaos in its undiluted glory, known as Chaos Undivided.
Each faction has it's own legions of mortal followers and Daemons who sacrifice uncounted millions of human victims to appease their dark masters. For, to gain in power, the Chaos Gods need souls. The Dark Gods reward their followers with 'gifts' who often come in the shape of a mutation, like a tentacle, inhuman strength or even daemonic wings! Eventually if the warrior (the Chaos gods care only about war, death and conflict) has proven himself enough, and has become a Champion of Chaos in the process, he will be granted immortality as his final reward. He (or she of something else entirely in the case of Slaanesh) has become a Deamon Prince and answers to his god alone.
The Chaos gods each reflect a particular facet of human nature and Chaos Undivided reflects simple and plain evil. Khorne reflects bloodlust and barbarity, Ngle the desire to tear down and to let everything rot and fester, Slaanesh stands for the desire for perfection and for ‘the pleasures of the flesh’ (Slaanesh has a disturbing preference for whips as weapons and tentacles as gifts) whilst Tzeentch is representative for the urge to evolve and progress, he also stands for the quest for (forbidden) knowledge and magic.
The symbol of Chaos Undivided is the eight pointed star as it resembles the four points on the compass that the Dark Gods occupy (being each others opposites and hating each other) and the different ways one can worship and follow Chaos.