My theory is that the Demon Gods feed on the spectrum of emotion, sweet and salty. Maybe umami too. So they reward some of them to feast on their pleasant emotions.
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So while I like the pretty metal idea of Cnauir being such a badass that he becomes a demon I can't square it with the Inchoroi. I mean their whole existence revolves around carnality and murder, entire worlds reaped and annihilated. Their Wracu certainly resist death and deform reality. How are none of them Ciphrang just waiting to shed their mortal bodies? They certainly don't lack willpower or conviction. They might only lack...belief?
I also believe that Ciphrang feed on emotion, however, I think they only feed on certain types of emotion -- negative ones, broadly speaking. Regret, sorrow, shame, guilt.
Gods are on the opposite end of the spectrum, as beings which feed on "positive" emotions, aspirations, desires, reaching, etc. Of course, I think the point here (as epitomized with the Inchoroi) is that neither end of this hypothetical spectrum is intrinsically good or bad, since it's all subjective or intersubjective.
This would also, at first blush, make the Inchoroi "angels" to the Ciphrang "demons". And the Inchoroi did descend from the Void (heavens), and historically were even referred to directly as Flesh-Angels, with the No-God being called the Angel-of-Endless-Hunger, and Aurang as the Angel-of-Deceit.