Well, in *City I Can't Remember the name of* the Templars seemed to even control their parent organization. They certainly controlled the government.
But the revolution as started by the mages isn't the one I'd want. Demonic possession is already dangerous enough when suppressed. It would be a widely used and dangerous tool under a revolution.
I think having your character work his way to the top of the city and secure power would have been a good storyline in itself.