It is possible for a human/vampire hybrid to exist: called dhampir, by Balkan myth and legend. Another hybrid exists in 'I Am Legend', (the book and the movie). Whereas the book calls them animalistic vampires, the movie shows them as a vampire/zombie hybrid. The Underworld series shows a Werewolf/Vampire hybrid, only possible though in one who has the original bloodline, however. In older myth and legend it was stated, that if one was vile enough during their time as a werewolf they were reborn as vampires whence they died. A chimera of all three is possible, but its appearance depends on the order on the order and level of infection.
