Life Blood — V.M. Black

She wanted life. He needed her blood. Cora Shaw will do anything to live. Diagnosed with terminal cancer in her senior year of college, she is given a choice: Call hospice, or seek out a mysterious man who promises an impossible -- and insanely dangerous -- cure. She knows him only as Mr. Thorne, a reclusive billionaire who is full of contradictions. A man with strange, impossible powers over her, who can turn even the darkest pain into intense pleasure. A man, she discovers, who is not a man at all.