Parmandur
Book-Friend, he/him
A nameless evil priest, with no set aesthetician or particular motives...Ah, okay. Thanks for bringing me up to speed.
I could see that working, and Venger certainly wears the correct color scheme to fit in with the cultists, but I'm not sure what it would add to have a wizard like Venger working behind the scenes when the adventure already has the evil priest heading up the cult and supposedly organizing the humanoid presence in the caves in some way.
Juat saying, they said they would use Venger, I would be amused if they did it here: and Venger is as much a Gygax joint as Keep on the Borderlands, in some ways.