Ivory Dusk. Dark Light, #6

For nearly a month, Hellfire has burned along the shores of the surface world. The apocalypse looms, and it is all Isabella and her angels can do to keep the creatures of Hell at bay. Until a new, far more dangerous demon walks into her life. He knows things Isabella has not found answers for, and has power she can neither explain nor ignore. In every way, this beast of a man should be her enemy. Yet he claims he is there to protect her. He is utterly unfazed by her divinity, mocks her attempts to threaten him, and dismisses the creatures she must fight with the flick of a wrist.
The demon called Ash is no less than Isabella's equal, perhaps stronger, and she should be terrified of him. Yet he stirs a desire in her she doesn't recognize, and delivers a pleasure she cannot deny. His name is Shreyan, and he is the first-born son of Satan. He was the first Archdemon ever born. And the one thing he wants more than anything else is revenge. Or it was, before he met the Archangel whose life he needed to protect.