Lord of Misrule by Rachel Caine
In the college town of Morganville, vampires and humans coexist in (relatively) bloodless harmony. Then comes Bishop, a master vampire who threatens to abolish all order, revive the forces of the evil dead, and let chaos rule. But Bishop isn't the only threat. Violent black clouds promise a storm of devastating proportions. As student Claire Danvers and her friends prepare to defend Morganville against the elements - both natural and unnatural - the unexpected happens: Morganville's vampires begin to vanish one by one. Discovering why leads Claire to one last choice: swear allegiance to Bishop...or die.