Angelfire by Courtney Allison Moulton
First there are nightmares. Then come the memories. Now she must hunt. Ellie can't shake the terrifying dreams about monstrous creatures that are hunting her, killing her. Then she meets Will and feels on the verge of remembering something just beyond her grasp. His attention is intense and romantic, and Ellie feels like her soul has known him for centuries. When they meet on a dark street at midnight, Will awakens Ellie's power, and she knows that she can fight the creatures that stalk her in the grim darkness. Will holds the key to Ellie's memories, whole lifetimes of them, and she can no longer pretend anything was just a dream. Her role is to hunt and kill the reapers that prey on human souls. In order to survive, she must also hunt for the secrets of her past lives, the dangerous and ancient battle of the angels and the Fallen, and truths that may be too frightening to remember. Angelfire is achingly romantic, terrifying, and filled with blistering action.