Book Four in the Celestial Series is The Daemon. This installment follows Grace as she navigates trickier aspects of her mission, which includes her own progression in her role as Savior to the Fallen angels. She's managed to get through the ordeal of the Atonement alive, but not all of her beneficiaries are grateful, including the escaped daemon Shax, who is all for remedying that glitch. Samael and Lilith are all too willing to even an old score as well. Grace remains subject to the limitations on her human half, which plunges her into the depths of grief and despair, even as she awaits the birth of her child with Benjamin. She is called to save the sinner, but finds herself stranded in unexplored territory when close proximity forces her to examine the privilege of being on the winning side of history.