From The Grey House:
That’s where the Slayers came in. They were sent by God to hold back the monsters. Most times, Slayers killed the monsters outright, even if there were humans around. Natalia didn’t agree with that. She felt there was a better way. She found she could approach most vampires if she were careful. Sometimes, she could approach werewolves, but they were trickier. Too close to the full moon, their rage was just under the surface. She rubbed her shoulder as the memory of Charlie’s betrayal came back to her.