Wilshire - Any theories on why Kellhus would be behind Meppa? That's the hangup for me. I don't know what the goal would be.
We don't have a ton of evidence, but wouldn't the Cishaurim be feared and hated in the New Empire?
Well my personal favorite crackpot is that Meppa is Moenghus' doing, but since you asked lets see...
Why would Kellhus be behind Meppa?
Kellhus obviously knew, or knew there was a good chance, that the empire was going to fall when he left. He took pretty much every able bodied man to the North, leaving a huge power vacuum. He was never able to catch Fanyal, so he was likely so swoop in when the powers that be were all elsewhere. We know that Kellhus can erase memories via the Whelming, maybe he doesn't so much erase them, but covers them up so that they are inaccessible to their owner.
So given all of that, Kellhus knew that Fanyal would leap at the opportunity to have a powerful ally - especially one that was a symbol of his peoples' former glory. Kellhus figured out how to teach the water-baring technique to one of his blind disciples (or blinded one of them and then taught them, whatever). He then erased this person's memories, and sent them off to find his enemies.
After Meppa, almost single-handily, takes over the empire, Kellhus can come back and give him his memories back (or maybe some trigger was placed in his mind so that once something specific happens his memories flood back). At the end of the day, only the face of the ruler changed,. Fanayal will be ousted as the face of destruction, but Meppa will be spared since he was basically under Kellhus' orders.
Uh so why go through all this? Kellhus couldn't find or stop the bandit for whatever reason. Maybe he wants him to take over his empire while he is away. Could be that he wanted to know if he was being helped by one of the Hundred, so he couldn't send a regular spy. He needed someone who looked like an enemy to the Aspect-Emperor, even to 'divine' scrutiny. What better person then the last scion of a cult he personally destroyed? To all the world and the Outside Meppa looks normal, but to Kellhus he is simply another set of 'eyes'.
Also, Kellhus is pretty sure he killed all the Cish, but how sure is he? Meppa could be a beacon for any wayward Psukari, and once they are all gathered, they can all be destroyed.
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Any questions? lol.