Daughter of the Blood by Anne Bishop
The world had been waiting for a very long time for a queen. A queen to heal that lands and punish those who selfishly ruled for so long. It was prophesized 700 hundred years ago by a black jeweled widow witch in her tangled web that a queen would come. This witch would wield more power than even the High Lord of Hell, and give him major headaches as well! The only thing is, she is young, and if she were to end up in the wrong hands, say a corrupted queen. She could be influenced to spread evil herself.