One Silent Night - Sherrilyn Kenyon

While mortals deck the halls and shop, an angry demon lord is plotting an all-out onslaught against the entire human race. Enter Stryker, the adopted brother of the legendary Dark-Hunter, Acheron. As Stryker prepares to engage in battle against the ultimate predator he must also face the deadly rage of his ex-wife, Zephyra. Original. \n \nWhile the world carries on unawares, Stryker, who leads an army of demons and vampires, is plotting an all out onslaught against his enemies--which, unfortunately for us, includes the entire human race. To avenge his sister, Stryker prepares to annihilate the Dark-Hunters. But things go awry when his oldest enemy returns. Enter his ex-wife. Zephyra. Just when he thought nothing could stop him, he's now embroiled in a centuries old war with a shrew who gives new meaning to pain.\n