Not sure if the idea has already been floated, but what if Iyokus has been dunyain all along? I don't know if I can trust anything from the text that the dunyain have truly been in isolation for the last 2000 years, for all we know that's just the story that fits Kellhus' conditioning. I feel like someone is going to be revealed as another dunyain in UC, but I was banking on the last surviving, insane scalper or Meppa.