Sweet Evil is the first in a trilogy about demons. Of course there is some mention of angels, but it really focuses on the demons. Anna, the main character, learns that she is the child of a demon, and that it is her job to tempt others to commit sin. The story is just great. I don't want to go into too much detail because the world building is done so well, and there are some great twists and turns. The trilogy continues with Sweet Peril, and concludes with Sweet Reckoning, which just came out.
I was waiting to write about this book because lately I've loved book one and two of a trilogy and just hated the third book. I was so satisfied with the ending. It was everything I wanted in the book. So I heartily recommend this entire series. Have you read it? What did you think?