He's trying to take over the world?

[She's not trying to have this sound glib, but it seems like Anhurr's motives are basically just "make everyone undead." She hasn't interrogated the topic much, and at the time the attacks were happening, she spent too much of it to resisting his pull on her to really find out about what's happening.]

He has a certain degree of control over people who died, or who have come close to death. So the more people die, the more control he has.