Well, to use a certain shout out, with what they did I wouldn't be surprised if they were practicing Word Bearers!
These two are...well, they're sick. I recognize sickness - and in some, it brings attraction to a faith.
This sickness brings them to justify their cruelest impulses with the favors of the divine. They had to be cruel, you see, to remain in the favor of their divine lord. They're never the head, the most powerful, they cast themselves as servants, to justify this sick obsession to themselves - for if they are just doing their work as a servant, what can they be accused of?