Ashes of Angels — Michele Hauf

As a muse, Cassandra Stevens had been warned of the Fallen angel who'd one day come to impregnate her with a nephilim, an evil offspring. But no one could have foreseen that Samandriel -- the raven-haired, silver-winged Fallen one -- would sweep her off her feet. Against all good sense, Sam stirred her suppressed desires, yet for her own sake she dared not arouse his carnal ones. For Sam had been summoned to earth by a dark vampire lord. And more Fallen were on their way. Despite the dangers, Cassandra needed Sam by her side, for only together could they prevent the apocalypse that had been unleashed...