It could go either way. I assumed he had been corrupted, but was always one of those "For the greater good" people, which is what gave Dracula an inroad. You know, this is the fellow who thought nothing of grabbing a random orphan kid and tattooing her full of doom magic. That, and there are lots of references to Ecclesia once being a fairlyy decent size (Shanoa is "one of the female spellcasters," for example), but clearly by the time of the game, it's down to three people. They probably quit as he got more and more extreme over the years. But this is all just my interpretation.