So the girls are vampire hunting. They really don't know much about the vampire yet, and, frankly, neither do I.
But I do know I hate to waste a monster, especially a high-level one, especially with a group of players that've never fought it before.
So I've been thinking about my options, and reading up, and thinking of how to wring every drop of doom and danger and scheming and minion and mood and campaign fuel out of the situation...
(No, you are not allowed to post "Don't worry what tha' other mofos, do! Just do it man! Don't overthink it! i'm sure whatever you think up will be awwesumm!" in the comments. Thinking is my idea of fun. Thinking about how I want this to roll is a pleasant problem to contemplate.)
What follows is not so much four different types of vampires (the pennangalan, the moroi, the strigoi, etc.) as four different kinds of ways vampires are treated in stories. Obviously, there are lots of other ways, (Abbot and Costello Vs. Dracula, for example) but I'm just talking about pre-modern stuff and modern stuff that copies the classic templates...
(Die! Dracula! Die!)
From this point of view, a vampire is a category of monster mainly distinguished by the fact that it requires special tricks to kill it. Sunlight, stakes, running water, etc. Like a medusa or a hydra. The tricks and rules are well-defined and usually adhere closely, in-game, to the tricks and rules the players know from out-of-game sources like TV and books. The theme of vampire-as-disease-victim (as opposed to vampire-as-curse-victim or vampire-as-personification-of-evil) is important since the idea that there are specific rules for infection is really important.
This is the obvious D&D default vampire.
The nice thing about this aspect of vampires is that there is more broadly-known and consistent lore about vampires than any other monster (like are wights vulnerable to acid? Who knows? But vampires don't like garlic, we all know that), so if you're designing a strategic or tactical challenge using the Old School D&D motto "player skill not character skill" it's hard to beat a vampire for a foe that PCs can really think about before kicking down the door. The more the PCs know about any given situation, the more opportunity there is to see the situation as a strategic challenge. Here are the rules--go!
Typically, if a PC ends up as a vampire, then it's hard to escape sticking pretty much to this model, since it's relatively easy to describe a vampire this way in game terms and then just let the PC do whatever they want.
Movies typically look at vampires this way for the most part because then they don't need as much backstory. Even profoundly arty movie vampires--like Werner Herzog's Nosferatu or Andy Warhol's Dracula, end up, despite all the metaphors involved, having a lot of the puzzle-monster vampire about them.
Spooky Screw-You Puzzle-Monster/Disease-Victim Vampire
(Everything you read in Dracula is wrong)
As above, only the DM goes on wikipedia, looks up "vampire" and reads something like this...
In order to ward off the threat of vampires and disease, twin brothers would yoke twin oxen to a plow and make a furrow with it around their village. An egg would be broken and a nail driven into the floor beneath the bier of the house of a recently deceased person. Two or three elderly women would attend the cemetery the evening after the funeral and stick five hawthorn pegs or old knives into the grave: one at the position of the deceased's chest, and the other four at the positions of his arms and legs. Other texts maintain that running backwards uphill with a lit candle and a turtle would ward off a stalking vampire. Alternately, they may surround the grave with a red woolen thread, ignite the thread, and wait until it was burnt up. If a noise was heard at night and suspected to be made by a vampire sneaking around someone's house, one would shout "Come tomorrow, and I will give you some salt," or "Go, pal, get some fish, and come back."
...and so, instead of the standard post-Hollywood stakes-and-sunlight model, comes up with some weird new vampire with new vampire-killing rules.
While using unfamiliar folklore to define the vampire has the advantage of making it spookier (at least if you go with the old-women-with-the-knives type of thing, the running-backwards-with-a-turtle thing might not exactly bring the arcane terror), it has the disadvantage of taking away the player-knowledge-comes-in-handy tactical aspect, plus it could be read as just a Fuck You from the DM if the players don't know about it ahead of time.
Ghost Story/Curse-Victim Vampire
(Dracula--Love Never Dies)
A vampire is what's become of an individual person with an individual history and so getting rid of the vampire involves somehow tying up the loose ends of that person's life or otherwise dealing with them, possibly in addition to the "usual" vampire-killing methods. Getting rid of the vampire will necessitate finding a lost love, righting a wrong, satisfing an oath, moving a symbolic object etc. The vampire's predatory nature is nearly always pretty obviously a sexual metaphor.
From this point of view the vampire is less diseased than cursed, his or her condition is specific to him or her. Though the vampire might be able to create more vampires with its bite, its own vampirism isn't necessarily the result of another vampire's bite (that would make the vampire less unique)--it could be some sort of divine punishment or the result of an improper burial. This kind of vampire can have unique abilities tied metaphorically or symbolically to its past or situation, and often enacts magical-thinking-ghost-type-behavior-patterns like, for example, if the vampire died by suicide then it lives in a well and tempts everyone who looks in or if the vampire's mortal body was killed by someone with red hair it always attacks people with red hair, etc.
In this case, the vampire is the center of a traditional ghost story--curses and taboos are in effect, and the PCs have to enter this system of spooky thinking in order to get rid of the vampire. It typically appears in an investigative-type situation.
(The closest obvious referent in D&D here would be Strahd from Ravenloft, who always seemed like a sort of a Castlevania-style Dracula-clone puzzle-monster sitting on top of a megadungeon with a little of the romantic ghost-story stuck on top. Probably the proportions of each vary from DM to DM.)
Sometimes aristocratic vampires are this kind of vampire and sometimes they aren't. It depends on whether you're supposed to be sympathetic to- or intrigued by- the aristocrat's history or whether his/her aristocraticness is just basically a metaphor for his/her vampireness.
In general, vampires are scariest when they aren't there yet--and the ghost story vampire emphasizes this aspect. S/he is just sort of an excuse for all the other moody and spooky things--like how in Lovecraft the actual monster is less the point than just the atmosphere of madness and terror that it generates. The plot is the real monster, the vampire is just the thing that gives it a center.
(Dracula--from dracul, meaning "dragon")
A vampire is like a demon or is a kind of demon. It personifies evil forces (generally ones associated with animalistic rather than civilized behavior), and while its nature is vague and insubstantial and partially metaphorical, it's extremely powerful. This is the kind of primal evil from the dawn of time found in the oldest myths and is often distinguished from other demons only by the fact that it drinks blood. It often looks more like a creature than a human. It does not scheme, it simply preys.
Slaying this vampire will require either epic-level skull-splitting with some sort of gimmicks that make the PCs the equal of the mythic heroes that killed these things back in the day or righting some sort of larger-scale spiritual or moral wrongness. This kind of vampire is, above all, blasphemous, and so the solution to the vampire, viewed from this angle, will often involve invoking piety, righteousness, or divine intervention.
It goes without saying that in most stories these kinds of vampire overlap--just as the classic vampire themes of disease, lust, and blasphemy overlap. But in looking at pre-modern vampire stories, it's usually pretty easy to fit the story pretty squarely into one of these three models.
Anyway, six first-level PCs against a vampire is going to be a long-haul adventure, so I've got a while to think about it.