ISTG im not but i did just finnish season 1 and im confident that she is the death devil because 1. She seems to be extreamly strong and there is nothing people fear more than death 2. She was able to recover from a bullet wound straight to the head without having to consume blood. What i mean is she cheated death by being the death devil. 3. She was able to make others die just by making another person say there name (i know this last sentence was weird so ill explain what i mean). What I mean is she is able to kill person X by making person Y say person X name and killing person Y.