Board Thread:Warhammer 40k General Discussion/@comment-14745711-20140911102114/@comment-6078851-20140915160159

the old ones 'broke' the warp 64 million years ago and that breaking is what allowed entities to coalesce, and to then eventually become the gods. nurgle seems to be the oldest canon-wise although many arguements can be, and have been, made regarding the possibility of tzeentch being the oldest (and possibly predating the warp itself, but while that idea is nothing more than speculation it does have some merit).

slaanesh was 'birthed' a mere 20 or 30 thousand years ago thanks to the deprevations of the eldar and their level of emotionality.

canon-wise khorne was 'birthed' during humankind's dark ages because of all the violence and death being perpetrated. what puzzles me about this though is that violence, bloodshed, death, and galactic spawning war, you know - all things khornate, existed in abundance long before humans had any effect on the warp, so logically khorne should have been birthed alongside nurgle from the war in heaven.

emps was born is around 40 or 50 thousand years ago and so the the realm of chaos would have been very potent by then (it was very potent and shaman souls were being devoured before their reincarnation resulting in their 'emps' plan), having been brewing for over 63 million years, and at the very least nurgle and tzeentch had both existed for a long, looong time. if the gods were to unite to send something back, not a primarch so as to negate the paradox, but a great unclean one or two then they wouldn't have to concern themselves with finding emps' family, the greater daemons could simply wipe out the entire planet, or more likely subjugate the planet thus ensuring their emotional contributions, or turn earth into a daemon world :P

also while the human race has contributed to the forming of warp entities the bottom line is that the chaos gods don't need the human race: there are plenty of species in the galaxy that contribute to the realm of chaos and some have a far greater impact than humans.

when 40k was just starting i think all the gods were 'birthed' by the human race (except slanesh who i think was still from the eldar), but as the franchise has progressed and deepened and things get retconned the human race's contibution to the realm of chaos has been lessened and parcelled out between other races. i've always thought that khorne's canon birth is something that should be retconned as it doesn't make sense given the context of the galaxy.