Any thoughts on where the Ork gods Gork and Mork fit into the 40K cosmology? I've been toying with the idea that they are misinterpretations of the Chaos Gods- Mork, god of strength and resilience, is an amalgam of Khorne and Nurgle, while Mork, god of speed and cunning, is a hybrid of Slaanesh and Tzeentch- but that doesn't really mesh with the fluff: Orks being created by the anti-Chaos Old Ones, and in any event predating the 'birth' of Slaanesh. So, if Gork and Mork aren't Chaos, what the hell are they…?
A mistake to many people make. The 'Big 4' aren't the only warp entities that can be classified as gods. It's oldschool cosmology that they aren't and it's never been specifically retconned either.
That Khaine is even Khorne has always been plays off as a big maybe. Gork and Mork have never actually been in doubt, while the rest of the Eldar gods (ie: not Khaine) only marginally moreso.
Each 'warp deity' is a product of the belief system that gave rise to it, like Vaul and Isha are results of unique elements of the Eldar psyche, as much as Khaine is. Even the Emperor could possibly ascend to 'Chaos God' status if his soul came untethered from his body. He was already a gestalt-super-immortal-psyker to begin with.
As for where Gork and Mork came from? I imagine it was an entirely unintended effect of the Brain Boyz losing control of the hordes and the Orks themselves adopting a belief system to explain their origins. Much like the Eldar did, forgetting it was the Old Ones who created them to be soldiers against the C'Tan (or whatever in the newest ed).
And as for why they don't fall. As others have said, the Waaaagh! energy generation by large clusters of Orks could have a dampening effect on the powers of Chaos. And the fact that Orks don't want anything that Chaos has to offer. He can always find a good fight, and he doesn't fear death, or injury.
In the most recent fluff Orks are not capable of falling to chaos, they used to be. There were even Khorne Stormboyz in one supplement.
Even back then it was a very rare occurrence for them to fall.
Edited by Blood Pact