Quote Originally Posted by Pojko View Post
I personally have never read anything detailing the relationships between the Chaos gods who we know don't utterly despise each other. It's always as you said, Nurgle and Tzeentch hate each other because of philosophical differences, while Khorne hates Tzeentch for magic and Slaanesh for being a prancing little fairy, while they hate Khorne for being a mindless brute.

But given that all the Chaos gods are rivals to each other there would be natural animosity between them and their followers if they're in the same place. Who knows, maybe Khorne thinks Nurgle is too jolly and that disease is a sign of weakness, Slaanesh thinks Nurgle is ugly and unsophisticated, and so on. You could probably think of a number of logical reasons why all the gods should hate each other based on their traits.
It was established in WHFRP3 that Khorne hates Nurgle because his corpulent indolence runs counter to the vitality and athleticism that Khorne embodies. Likewise, he also hates Tzeentch because he embodies dishonesty and cowardice, which runs counter to martial honour, which is another aspect of Khorne.