The short answer is, you can’t really have vampires that kill
every time they feed. I’ll go into the details in a minute, but the solution is as simple as the problem, don’t.
We’ve said this before, but there are
no such thing as vampires. I don’t mean this in the, “well, they’re mythical creatures, so they’re not real,” sense. I’m talking about how there isn’t a single, universal, vampire myth.
Vampires are a persistent fear lingering in the back of the human
subconscious. Originally just a fear of the dead, and what might happen if funerary rights weren’t properly observed, and later as an expression of of Victorian hangups over sex, and xenophobia. As a result, there is no, true vampire myth; they are as varied
as human cultures that created them. There is no unified set of rules for how vampire behave, what they can do, or what can kill them. You set the rules, and need to tailor those to fit your story.
This includes things like their powers and weaknesses. If you want vampires that walk in the sun, you’re not “ripping off” Twilight. Sunlight vulnerability is a possible weakness, but it’s hardly universal. The same is true with immortality. Some vampires in myth have a very limited shelf-life, and then die… again. Even the need to feed on blood isn’t universal. I doubt anyone’s clamoring to write about vampires that literally survive on human fecal matter for 40 days before dying, but the myths are out there.
Your vampires? Your rules. You don’t need someone else telling you what they can or can’t do, because there is no universal kind of vampire.
That said, running with the idea that vampires kill every time they feed, or turn everyone they feed on, will run into serious logistical problems, quickly. Even if you want to run with this, it’s worth thinking about, because it will push your story in very specific ways.
For killing, the issue is dead bodies. Last Year, NYC reported around 350 homicides, total. The highest annual Homicide rate for the city was around 2,250 in 1990. If you have a vampire that needs to kill every night, would, on their own, double the modern the figures. Even in the 90s, you couldn’t slap another 365 homicides on the pile without raising a few eyebrows. Even if you scale it back to once a week, an extra fifty two bodies a year on the pile will, still turn heads.
And that’s for one vampire. If you intend to have a community, then all of them need to eat, and the numbers above multiply. Maybe if they share their meals, that’s more viable, but it’s still a lot of bodies. Where you have a lot of bodies, you’ll have a lot of pissed off relatives, and, inevitably, vampire hunters.
Vampires that turn everyone they feed on run into similar problems, except there problem is geometric. If you have vampires who turn everyone they feed on, and need to feed once a week. Starting on January first with a single vampire, by the first week of February, you’ll have 32 mouths to feed, and by mid August of the same year you would have, by necessity, converted every single human on the planet. (Specifically around 8.6 billion by the 34th week.)
So, the simple answer is to look at vampires as parasites. Sure, they may think of themselves as apex predators, but at the end of the day, they’re still ambulatory leeches. Wandering the night, and chewing on unsuspecting coeds. In most settings the best way to approach that is to make themselves as undetectable as possible. No dead bodies, no hoards of the undead wandering around, just parasites, with delusions of grandeur, picking at the human population.
If vampires killing or turning their victims are the exception, rather than the rule, it changes the dynamics, and the entire thing becomes a lot more functional. If you have a vampire who does kill his prey, it gives the other vampires in his city, a very specific motive to hunt him down as fast as possible, before he draws unwanted attention, and puts them all in danger.
Even if you’re running a setting where the vampires are out in the open, and in control of everything, a rogue vampire killing their meals is still a threat to the food supply.
A rogue vampire constantly turning others is an immediate threat to the other vampires. If he’s raising an army, then what does he need it for? And who is he going to use it against? Short answer? If you’re not his friend, it might just be you.
Anyway, if you’re unfamiliar with them, the two things you should take a look at are Ultraviolet and Vampire: The Masquerade. There’s also Daybreakers, which might give you some ideas for vampires who are operating openly and in control of the world.
Ultraviolet was a British TV miniseries with Idris Elba and Jack Davenport that has no relation to the the American film. Ultraviolet focused on a group of paramilitary vampire hunters sanctioned by the British government. Wtihout going into too much detail, it does a fantastic job of examining vampires dealing with the threat of a man-made apocalypse, and planing accordingly.
Vampire: The Masquerade was an Urban Fantasy RPG focusing on Vampires. It’s part of the larger World of Darkness setting. It owes a lot to Anne Rice’s novels, but the resulting setting spends as much time explaining why things work the way they do, as simply saying “these are the rules.” It also has some vastly different takes of vampires, ranging from aristocratic puppeteers to sewer dwelling monstrosities preying on street people.
Daybreakers is a very good look at specifically violating some of the rules I listed above. It’s vampires are highly contagious, and as a result the vast majority of the population. As a whole, the film is an allegory for oil consumption, but it’s worth looking at if you’re wanting a post apocalyptic setting where vampires have decimated to the human population to near extinction.