Captive soul - Anna Windsor

She's definitely getting warmer.

Her flame power nearly extinguished in a battle against the dark forces attempting to control Manhattan, fire Sybil Camille Fitzgerald is down but not out. Joining a new squad of warrior witches, she hopes to reclaim her fighting spirit and, with luck, her pyrotechnic mastery. Two problems on that front: a new army of cannibalistic demons and her superheated lust for John Cole, an unholy blend of demon and U.S. Special Forces agent now working undercover for New York's Occult Crimes Unit.
John knows he can't be trusted-hell, he can't trust himself. His warrior soul has entered a new, supernaturally fit body. Unfortunately, it's a body belonging to the Sybils' worst enemy, whose supernasty essence still lingers. But when John's demon energy seems more alive than dead, it's Camille whose scorching kiss keeps him human-for now. All he's got to do is master his dark side and save Camille and the Sybils from an army of satanic hellboys planning their ultimate destruction.