Kingdom of Ashes (The Devil's Bargain, Book 1)

(Previously published as DEVIL WITHOUT A CAUSE)
Samael the Fallen, once an angel but now cast down, has reigned for eons as High Prince of Darkness within the depths of Sheol. His tricks are many and his powers are strong, but eternity as a fallen angel is a lonely existence, and Samael's most recent dealings with mortals have left him more aware of that than ever. When an old friend, the Archangel Gabriel, offers a final opportunity at redemption, Samael the Wicked, Seducer of Souls, must decide whether there is anything of the angel he once was still lurking within his own heart, or whether the Darkness within his soul has claimed him forever.