Phantom
by Christopher Pike, 1996
Series: The Last Vampire Series

"After five thousand years she was again mortal. The dead alchemist's experiment has worked. Alisa is no longer a vampire, but a frail and confused human. Not only that -- she is pregnant. The baby grows in her at supernatural speed. As the stranger watches. The stranger from the past. But what child will Alisa's seed produce? A demon or an angel? Alisa does not know. But the stranger does. He knows everything that ever was. And he knows everything that is to be." (From Amazon.com)

Paperback Info: ISBN 0671550306, Simon Pulse