Board Thread:Warhammer 40k General Discussion/@comment-92.97.77.182-20130321145115/@comment-3186669-20141003142800

Then you're missing the point of Chaos within the Warhammer universe. It feeds off the negative emotions, so is impossible to "defeat" while the emotions exist. Given that humanity are the more widespread species in the universe (with the exception of orks, who don't respond to Chaos as they don't feel the emotions required), removal of humanity would remove the source of sustenance for the Chaos powers.

How would you expect to remove beings created from pure emotion without removing the source of the emotion? If you've read the Inquisition War trilogy, they try to use a being called the Hydra to unite the minds of infected people to force Chaos back, but without enslaving the will of all humans in the universe, it's otherwise impossible.