For most Gloranthan religions, Chaos is something outside of the realm of gods and spirits. There are a few gods or spirits that were corrupted by Chaos or who otherwise embraced it during the Greater Darkness. The Orlanthi, Praxians, Malkioni, Doraddi, and followers of the Old Gods (animism) all agree on this.
Most celestial cults agree as well, but Yelm is oddly associated with two Chaos gods – Nysalor and the Red Goddess. Perhaps it is Yelm’s claims to universal rule, which would include Chaos along with everything. Or perhaps it is Yelm’s inability to see his own Shadow.
And yet Yelmalio does not have those same associations. It is a curious link with Yelm.
The mindless devouring maw of Chaos continually threatens Glorantha’s existence. In the Greater Darkness, existence very nearly ceased. IFWIW, Arachne Solara and the Net of Existence – these are mythic events where existence itself was able to continue due to the deeds of one who was all.
Deities such as Orlanth, the other Lightbringers, Storm Bull, Babeester Gor, Yelmalio, Zorak Zoran, Kyger Litor, and Magasta are very much defined by the struggle against Chaos. They fought terrible rear-guard battles against Chaos to continue to exist. It is not surprising that their cults hold true to that.
At a certain level, the Red Goddess is something of Wittgenstein’s duck-rabbit. Does she threaten the existence of the cosmos or does she liberate us from fear? Both can be true, depending on the viewer!
Entities like Thed, Ragagnalar, etc. are not invoked in most magical ceremonies or heroquests – unless they are specific enemies to be overcome as part of a magical defeat of Chaos. Death, disorder, and lies are all part of the cosmos – but Chaos is outside of it and antithetical to existence.
Getting back to the original thought, most Gloranthan religions hold that Chaos is “outside” of the cosmos. It precedes it, and the cosmos was formed out of the Primal Chaos. Chaos is an assault on the existence of the cosmos itself and is thus wholly different from every other element or power. To analogise, the other elements and powers are jostling against each other within the confines of the cosmos; Chaos threatens to return the entire system to where it came from – the gaping maw of Chaos.Illumination allows one to understand that is not per se evil and not to fear or hate it. But for everyone else, that is a bridge too far including for Chaotic tainted beings such as broo, scorpion men, vampires, ogres, and the like.
So regardless of how dangerous, treacherous, or even evil deities like Zorak Zoran, Eurmal, Gorgorma, Wachaza, or Gagarth are – they are “of the world” and still preferable to things like Thed, Vivamort, Primal Chaos, the Crimson Bat, or Krarsht.
There is evil and there is EVIL. And many cults that consider deities like Zorak Zoran to be an enemy and evil find him a lesser evil than Chaos.