A possible origin of the vampire myth:
The myth, established well before the invention of the word “vampire,†seems to cross every culture, language and era. The Indian Baital, the Ch’ing Shih in China, and the Romanian Strigoi are but a few of its names. The creature seems to be as old as Babylonia and Sumer. Or even older.
The vampire may originate from a repressed memory we had as primates. Perhaps at some point we were — out of necessity — cannibalistic. As soon as we became sedentary, agricultural tribes with social boundaries, one seminal myth might have featured our ancestors as primitive beasts who slept in the cold loam of the earth and fed off the salty blood of the living.
I don’t buy it. Cannibalism proper definitely has deep-rooted archetypal meaning, but blood-drinking is different. While vampire myths vary have evolved over the centuries (the vampires of the Buffyverse are vastly different from Bram Stoker’s vampires, which are vastly different from the original Eastern European legends), the one common denominator is that the vampire is dead.
[one common denominator is that the vampire is dead] Dead yet somehow living, and wholly separated from the gods that ruled any given monotheistic religion. I suggest that, seeing it is a fact that there have been cannibals over time, as the religious pious spread out over the globe (inclusive of ALL monotheistic religions that have the desire to convert others, but none more so than Christianity) they fabricated the idea of the vampire to persuade cannibalistic societies to give up this tradition in fear of remaining separated from said religions’ gods.