Descent - Outcast Angels, #1

Escaping heaven was only the beginning. Faced with the choice between fighting in a war they never wanted or betraying their maker, Fomor and his angelic companions escaped to Earth and became the Rephaim. After decades of wandering, they find a new home, and a new purpose in protecting the humans they have come to love. But evil cannot be avoided, it must be destroyed.When demonic forces bring Heaven's war to Earth, threatening to enslave humankind and create supernatural soldiers with blood sacrifices, honor and love demand that the Rephaim fight back.
But the battle will cost them more than they know, and one of their own will pay an ultimate price. As the fate of the Earth and her inhabitants hangs in the balance, Fomor and his companions must win the fight for their new lives or watch as the world is annihilated. Poised on cliff-edge of fantasy and history, this epic adventure does not disappoint.