It's a very ancient in its origin I dare say, having been practiced for thousands of years. Since biblical times, or perhapse before. I read books about ancient mysticism, dark 'magic' , alcamy and ancient stories/myths and I find that often the drinking of the blood of the innocent is an all too common ingredient in the dark ways. A pattern. Not sure you'll find a name of someone who 'discovered' it, for it has been a protected knowledge for some time. Pagan/Cannibalistic origins perhapse.

Vampires for example Im lead to believe are a literal and metaphorical analogy for these evil ones. They are ancient in their ways and knowledge, surviving elongated lives through the consumption of blood in ritualistic torture. Virgin children being a favorite. They hate or are hurt by the 'light'(knowledge or exposure) as they dwell in the shadows and darkness. Their goal always seem to be reaching an elite position of control and authority so that they may operate openly. Vampires are often depicted as being incredibly jaded and disassociated, ever striving for more thrill as their humanity is lost. Almost exactly how adrenochrome side effects have been explained to be. They also are depicted as cultists who warship satanic idols and gods. Conjurors of named demons and ungodly chimera.

Sound familiar? These tales are very old. And yet they still adequately express symbolically what we are against.

There have been great decodes about the symbology and stories around vampires and werewolves if you are interested.