Everything you need to understand or teach Children of the Night by Mercedes Lackey.
The main theme is the existence of evil in the world. Fighting it is the duty of all who are able to do so. Diana Tregarde has been "called" to this responsibility by her unusual psychic strengths. She is a Guardian — a commission which has little to do with her neopagan faith. She is required to respond to anyone who calls out for help on a psychic plane.
Diana is contemptuous of...