The way Eshonai "died" at the end of WoR and the Parshendi that escaped leads me to believe she may transform back to a non-odium form and help gather the rebels. I hope at least. The Parshendi themselves don't actually seem evil, it's more like they fought a losing war with the humans long ago so they turned to get more power which corrupted them. I can see the humans of today and Parshendi that aren't converted finding some kind of peaceful arrangement to help end the desolations.