They can make their own enormously useful long-term immortal tools out of mortals, and in doing so almost guarantee that mortal's subservience. Chaos Gods don't really go in for reaching mutually beneficial arrangements with other powers, and when they appear to be doing so it's always a pretext that ends with the being who thought they could meet a literal Chaos God halfway getting either destroyed or enslaved. That's why Chaos is often described as 'self-defeating' - because each of the Chaos Gods always wants to do things on their own terms, and will absolutely detonate an arrangement that only gets them 99% of what they want in favour of making a play for 100%.
There probably has been vampires at points in history that thought that the Chaos Gods were the One Weird Trick they were looking for to defeat their rivals, and I guarantee it ended in disaster for them every time.
You know, this post has me thinking about whether there's more to Dhar and the Chaos gods than just Dhar As Force. Because one thing that makes people operate like that is when they see the world as a zero-sum game. It would certainly fit with Dhar's thematics of Blood and Sacrifice if the fundamental thing going on there was a situation of One Must Lose That One Might Gain.
And if the Chaos Gods are so strongly of Dhar then to them, any deal in which they aren't 100% in the winning side is one where they've lost something. Which would fit with that behavior. They act in a predatory manner and, to a predator, a situation in which their prey got something
from them is a situation in which they were wounded. Better to hedge their bets, blow the deal up entirely, than to risk that wound weakening them. Especially when there's always the other three, and the would be usurpers, always waiting in the wings to take their place.
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Which, to head off on a tangent about an old hypothesis of mine, would of course imply that just as Qhaysh opposes Dhar by being the persuasion to Dhar's coercion on the mystical side, it also opposes it by being the Positive Sum (E: Or Positive Feedback Loops) to its Zero Sum elementally. It would certainly fit well with the absurd power of some feats of High Magic if the winds aren't just cooperating in harmony, but nourishing and enriching each other in the process.
One wonders if that hypothesis might not be testable in an particularly elemental windherding of
Azyr and
Aqshy.
Azyr as the wind that fans the firestorm and
Aqshy as the conflagration that draws the winds. Or many other ways. Light and Shadow defining each other via a third wind as an intermediary, for instance; "Things that feed upon each other and grow stronger for doing so" seems like a particularly rich metaphor for designing spells and enchantments around the Elemental side of winds.