The Killing Dance by Laurell K. Hamilton
The Killing Dance is the sixth in the Anita Blake: Vampire Hunter series and continues the adventures of Anita, Jean-Claude and Richard, and it takes place about one month after the previous novel. This book starts out with Anita sizing up a potential client for her necromancer (zombie raising) skills with Animators, Inc.
However, the tables get turned on Anita when she is contacted by the assassin, Edward. Apparently, Edward has received a contract to kill Anita. Anita is as close of a friend as Edward will ever have, so he turns down the contract and advises Anita to start making plans for her own protection. It will only be a matter of time before someone else accepts the contract for her life.
On the shapeshifter front, Richard is forced to protect one of his wolves from Raina, a sadistic werewolf with a thirst for violent pornography. Raina is the mate of Marcus, the current Ulfric (leader) of the local pack. Richard is forced to make a move as pack leader and declares Anita his Lupa (mate). Anita eventually kills Raina (ah, but this isn't the last we'll hear of her).
This is the first book in the series where we see Anita, Jean-Claude and Richard as a true trio. Both Anita and Richard received the first two vampire marks from Jean-Claude, so they are now tied together by blood. The sexual tension in this book has reached a fevered pitch - from this book forward, Hamilton only increases the sexual adventures.
This book title represented a slight variation on Hamilton's practice of naming the novels after a fictional location. The werewolves in this book refer to both sex and dominance fights (particularly the fight to become Ulfric which must end in either the death of the current Ulfric or the death of the challenger). This fight is known as "the killing dance."