The Salvation of Gabriel Adam — S.L. Duncan

Embattled by an uncertain future, Gabriel Adam is now slowly succumbing to the powerful ring that he credits with stopping the demon sent to Earth to start the second war between the light and dark realms. As his health fails, his feelings grow for his archangel friend Micah. With the inevitability of his future ever nearer, he wonders if time is left to rekindle what they once shared.

But a darkness is growing in Istanbul. Lilith has used her alluring beauty to manipulate Simon Magus, the new Turkish president, into giving her great power. Wanting only to reunite with her one true love, she seeks to find seven ancient vials and pierce the veil that separates the dimensions, unleashing hell upon the Earth.