Here are some religious/biblical references. If you read between the lines, you can clearly see all the clear inferences/references to blood sacrifices, vampirism, and the dark arts disguised as religious BS.
Similarly you can find much more of the same if you check out any encyclopedia or book on Judaism, Christianity, Islam, or Hinduism. Note that in the practice of all these sacrifices, it tis the priests who are entitled to the blood from the ritual! (and sometimes a portion of the flesh)