Vampyrism is a "condition" or trait that can be found in a person/being regardless of kintype or species.
Demon is a very broad term used for a lot of different and unrelated things.
If there's some term (or description), more specific than vampyric demon, that you could use, then that might get you more information.
Either way, welcome to the forums.
"Those who can't approach discussion with a basic level of intelligence and maturity shouldn't expect to be taken seriously." ~ Qualia Soup