Hunter by Blood — Robin White

In the middle of a job, Kayn is bitten by one of the werewolves he is hunting -- and wakes up one of them. Except he doesn't shift like he should, and he's not an out of control monster the way he should be. Unfortunately, the key to figuring out what makes Kayn different -- and possibly more dangerous -- may be found in the past that he prefers to leave behind …