I think Stephen Rooney took inspiration from the vampire lore you're talking about. D&D in general doesn't have a lot of vampire lore... most of it is from 2e and Ravenloft. I've read the Ravenloft novel "Vampire of the Mists", where a vampire wanted to turn a human lover who was dying. He couldn't get her to drink his blood after he drained her to the brink of death, which meant when she turned, she would be his slave instead of his mate. In the story, this took place in Waterdeep. So it's not like it was a different world. The blood consumption is significant.
