I voted kidnapped and "brainwashed," but honestly I'd be happy either way. I think it could be cool if they made us think it was one or the other several times throughout the story before fully revealing it, and it would be even better if there was more nuance than true believer or kidnapped. Maybe the truth lies somewhere in the middle? Whatever it is, I imagine that aspect of the story has already been fixed by this stage of development. It's releasing in a few months!
