Death Masks (Dresden Files Book 5) by Jim Butcher
Dresden, who started a war between the vampires and the White Council, is challenged to a lethal duel by a vampire nobleman of the Red Court.
All three Knights Of the Cross get involved in a parallel plot involving some powerful demons who have turned the 30 pieces of silver given to Judas into powerful totems that possess humans.
Dresdenís former girlfriend Susan helps him; she is a semi-vampire herself now, taking advantage of her vampiric skills and strengths as she works against the vampire establishment. Complicated and exciting.