Living Legend by Allie Shante

She's been called from her place in the darkness to aid the side of good in the last place she wants to be... Dani, groomed by Lilith herself, has long been spreading horror in the murk of purgatory. She never asked to be summoned to Heaven's Gate and never expected to be charged with the stubbornly attractive angel Nicholas as her partner. Though, with a face like his to look at, Dani isn't about to complain. The lines between good and evil are shifting. Dani discovers that, lurking in her familiar darkness, are secrets she would never have guessed at and doesn't understand. Now she must ask herself, who is a demon supposed to trust?