erttheking said:
Or am I just shooting in the dark and are vampires a lot like demons and that the author can do whatever the Hell they want with them?
Do you seriously need to ask this? A fictional boogeyman born of scraps of mythologies? Short of meeting a real life vampire, you're gonna have to accept that they aren't actually real and thus can in fact be anything the writer wishes. A vampire can be absolutely anything, there are no scientific laws or hard and fast rules.
Generally though, they should at least to conform to one or more of the most common tropes associated with them, in particular, the dependence on blood. That's really the main crux of vampirism, anything else is optional. Can/cannot walk in daylight, is/isn't afraid of holy water/crucifixes/garlic, immortal, sleeps in a coffin, tacky Romanian accent, no heartbeat, wooden stakes, can fly/turn into a bat, reflection in the mirror, all of these are optional (though the sunlight thing is almost as common as the blood thing but not the defining characteristic).
I quite like the "Void City" implementation of vampires, the book series by JF Lewis. There are four "strengths" of vampire, and they get various abilities in different combinations, perhaps by just luck of the draw. Speed, shapeshifting, inability to eat real food, paralysed by staking. All body fluids in a vampire are replaced by blood...tears, saliva, snot, phlegm, semen, even sweat (this in particular leads to some very funny imagery). Very funny, if sometimes vulgar book about an amnesiac vampire named Eric with girlfriend troubles and a best friend who keeps trying to kill him though he can't actually remember the attempts.
