It's almost as if the Cishaurim (not sure about the Fanim in general) were the antithesis of the Dunyain:
- Dunyain are all about reason, trying to breed out emotion.
- Cishaurim magic relies heavily on emotions, rather than reason. They are also the prophets/priests of the Solitary God, if I'm not mistaken.
Kellhus had this figured out in TTT upon seeing his father and thereafter setup the stage for Meppa's extreme emotions, for a purpose that remains to be seen. I expect such powerful emotions and Water are necessary for something to do with The Plan.
I get the impression the Solitary God 'shed' his various aspects and in doing that, created the gods/demons/whatever, keeping only the essential aspect, being emotions. The Gods in turn seem to lack this, and possibly need to feed on mortals who die. It would explain the world as a granary passage, as well as explain why the Fanim view the Hundred as demons. But I can't back this up, apart from the Head on a Pole passage whare we see things feeding on mortal emotions, as well as the damnation views by Mimara.
It may be that the Solitary God is not supposed to be read as "the Only" God, but as "the one from which all other gods came". Solitary apparently is also a word for a hermit/recluse, which is another similarity to the Dunyain/Ishual.
I know I quote the song about Anarlu's head often, but I still think there's a link between that and the story of the God(s).