The Darkest Touch (Lords of the Underworld, Book 12) by Gena Showalter
Torin... the most dangerous Lord of the Underworld.
Fierce immortal warrior. Host to a deadly demon. Torin's every touch could cause deaths. For Torin, indulging in carnal pleasure is utterly forbidden. He has always overcome temptation with an iron will, but now his control is about to shatter.
She is Keeleycael. The Red Queen. When she escapes from a centuries-long imprisonment, the desire that simmers between her and Torin is scorching.
His touch could mean her end, but resisting her is the hardest battle he's ever fought - and the only fight he fears he can't win.
'Gena Showalter never fails to dazzle' - Jeaniene Frost