A slayer. In Aaron's world, she'd be called a genocidal maniac, but if vampires in her world are like some of the unpleasant ones he's discovered here, sometimes he can't blame people for certain prejudices against anyone that might fall under the term. Even if he is personally insulted.

"Yes, well, as much as I'd like to discuss our personal views on the matter, I do have a suspect to place in a holding cell. You're welcome to accompany me to the nearest station. With the size of the group that has organized this attack, we will probably need help, if you're the kind who might be willing to provide it."