Board Thread:Warhammer 40k General Discussion/@comment-14745711-20140911102114/@comment-25177957-20140916205503

Sure all races feed the Chaos gods in some way, but Humanity not only can be fed off of, it is the most easily corruptable as we all know. Humanity (with the exception of the Orks and Tyranids) are the most numerous race in the galaxy, And the Chaos Gods obviously knew that if they allowed humanity to thrive it would be easier for Chaos to thrive. There are hardly any Eldar to feed one Chaos God, the Tau aren't vunerable to Chaos, the Orks don't have the thought capacity to turn to Chaos, the Tyranids have no souls and are simply biomass constructs, the Necrons possibly feed Khorne, yet since they're souless and emotionless they don't do much for Chaos. And while we have other xenos species that worship Chaos, they're usually in extremely low numbers. The Emperor recognized that Humanity was at the greatest risk of feeding Chaos with it's actions. This is not to say that the Chaos Gods only see Humanity as vital to their existance, since they were feeding off of the Eldar before the fall. That means that even if Humanity were extinct, the Eldar would still crumble and almost every other race (besides minor xenos races) would be neigh worthless to Chaos. There would be no race to fill in the gap like Humanity fills in, and that is due to non-Eldar xenos lack of emotion or dedication. Now I do believe that the Tau will eventually develop psykers in a few thousand more years, which will allow them to be vunerable to Chaos, and the Chaos Gods probably already know the Tau will grow and flourish, that could be part of the reason a warp storm prevented the Imperium from launching exterminatus on the primitive Tau.

To the Chaos Gods, the galaxy is like a garden. When you grow a garden you wait for it to grow and expand, and once it's quite full you harvest the garden. But to allow it to grow, the garden must also be protected from insects and plants that grow large enough to block out the sun from other plants. The Chaos Gods are more manipulative than it seems.