Are vampires evil? Do vampires worship the devil?
Yes. Vampires are innately evil. They must be because as the undead, they lack human souls. Plus, they are driven by blood lust which means they must consume blood and usually kill things. If a vampire is killed somehow, most stories have them going to Hell.
No, being an evil person is something that you have to choose, not something you’re born with. If you are a non-evil person before coming into your vampiric nature, you won’t suddenly ‘turn’ evil. Just like with normal humans, it’s the individual who is evil, not the species. Secondly, a person’s religion has nothing to do with whether or not they are a vampire. Vampirism is something you are born with, like height or natural hair color, and religion is something that you personally decide to put your faith in. Vampires can be of any religion; Christian, Jewish, Buddhism, Hindu, Pagan, Atheist, Agnostic, Satanism, etc.