writersoul
I presume that the vampire in question is biting and sucking the blood of a human which is permissible as long as the blood has not gone out of the body. The vampire sucks the blood directly from the neck to his mouth. However if it came out of the body into the air and the vampire sucked the blood off the skin it would be prohibited by the rabbis.
I wonder if they have a coffin in their living room. I am told they are very comfortable and they make a good conversational piece.