The enemies that encountered in the game are demons and other dark creatures who followed both The Count and Lord Malachi, hellbent to revive the former and plunge the world into the darkness by sacrificing all members of Patterson family. If James died at the hands of either Malachi or The Count, Malachi will rise and lead the forces of darkness conquering the world...
Gypsies are locals who swayed into the service of The Count.
Deceased humans revived as lesser living corpses. Weaker than vampires, but still packs quite a punch.
Vampires are once humans, but revived and/or corrupted by demonic forces and became bloodthirsty shadows of their former selves. Some such as Desmodiij and Demodus became powerful enough to evolve into demons.