Well, this is an info dump for a series of vampire stories I've had in mind for a while now. Let me know if anything doesn't make any sense. I wrote the last few bits while very sleepy. Hope you enjoy the read though!
The Original 12
The Original 12 Vampires arose from the Mire of Damnation, a foggy, swampy pool somewhere between Hell and Earth. They are a physical manifestation of all the Earths sins, released from the human body in death. All the sins and lost souls find their way to the Mire and after centuries of the excess settling at the bottom, the twelve original vampires were born.
They are a bit taller than a man, black, thick and leathery skin, pointed ears and teeth, vile red eyes (bloodshot), wings.
Holy Water and silver weapons can kill them much easier than iron can. Holy Fire is the best weapon but takes a lot of magic and prayer.
They can easily turn a human or create Ghouls to serve them (only the original 12 can control their ghouls, regular vamps would have to condition and train them). Some concentrate the ghouls into a large hive, others have their vampires and ghouls living in smaller, more dispersed groups.
Holy Blade, Holy Fire
The Original Twelve can be easily killed by Holy Fire. More specifically, with a bow and arrow made from the bones of an undead, and soaked in holy water for 40 days and nights. The lords prayer must be recited in Latin for each shot fired, which if it hits will cause the vamp to burst into flames. If this hits a regular vampire they just explode in holy flames and guts.
There is also a version that can force an original vampire to reveal its true form (they can morph into a human form by cutting their wrist and mingling their blood with a persons).
Vampire slayers later find out that using the same methods of holy water and undead bones, they can make a holy blade, recite the prayer, and slay the vampires with a flaming sword.
Vampires
Once human, now a blood sucking maniac. These are the people that have been turned by one of the Original Twelve Vampires, or another vampire like themselves. They are endowed with strength, sometimes intelligence, and an infinite life span, better senses, and a heavy burden.
While their general weaknesses are silver, and holy water or fire, things like regular bullets and weapons, and a bus can still kill them.
In the early days, after the terror of the vampires died down, and the slayers created secret societies dedicated to hunting down the Original Vampires and their descendants, there was order and stability.
Most vampires had a code and general rules that they followed. Such as, if you don't have enough self control to leave a victim alive, put on a glove (touching silver or contact with holy water burns their skin) and put the ghoul down before it can cause any trouble.
Most vampires were either hermits or well integrated into society, often becoming successful noble families and some even kings and queens. If a vampire was found to have been causing too much of a ruckus (leaving too many ghouls or bodies behind, betraying their secrets to humans) their brethren would often hunt them down, or hire slayers to do it.
Then, there is the hunger. Every vampire hungers for human flesh, but this is something they must fight to control, and most gained great control over their impulses. Those who did not would slowly be driven to insanity, and their body would undergo horrific changes.
Increase in muscle mass, longer and sharper teeth, claws, increased height and strength, fur, the beginnings of an animals snout. Only their faces, hands, and chest would be free of the dark fur.
These beasts were few at first, and were always hunted by vampires before they could cause too much damage. If a vampire was suspected of consuming human flesh, it was the responsibility of others to put them down before they could finish transforming and going crazy.
In more recent years, the number would vampires would grow and they would get out of control. With many leaving behind thousands of ghouls, and many becoming beasts.
Were-Beasts
Large, hairy, strong, and ugly. These monstrosities developed a taste for human flesh, and have paid the consequences dearly. Feared, hated, and hunted by human and vampire alike. Once turned, like everything else, the only cure is death.
These abominations can be found in the darkest and creepiest crevices of the earth. They come out at night to hunt, first in the countryside, then later in abandoned cities and towns.
As with the rest, silver and holy water or fire work well on them. But they can be felled by normal means.
It is every vampires responsibility to fight the hunger within or pay the price. The cost either being an eternity of savagery and insanity or death.
Ghouls
Ghouls are the unfortunate victims of vampires who weren't responsible enough to put down their victim. They are zombie like (minus the rotting), feral, and bat shit crazy. All they crave is
human flesh, and because they don't clean their teeth a bite from one can be highly infectious (not like a zombie infection, here you can just get incredibly sick and die).
Without training or conditioning, they don't listen to anyone except an original vampire. The OG Vampires have to either turn the ghouls themselves, or have a vampire they themself have turned create one.
A secondary creation ritual must be followed or the ghoul will just be another ghoul made by a regular vampire (and will not follow orders). A cross must be etched onto the ghoul's forehead with a silver blade, and the Original Vampire must mingle their blood with the ghouls.
Over time, Ghouls become more ravenous and start to shed body hair, and their fangs and claws grow longer and sharper to a point.
A responsible vampire will, once they have drained their victim (if they choose to drain the human until death) stab the corpse in the heart with a silver blade. That is the only way to stop them from turning, however, once they have turned any ordinary means can be used to kill the ghoul. Although silver is slightly more effective.
An irresponsible vampire will allow their hellish abomination to murder and eat cows and humans alike.
Slayers
Sworn to protect humans and destroy evil. The first vampire hunter soon came to form the secret society, which eventually spread to chapters across the world. They would use their holy magic and silver weapons to hunt the vampires for centuries.
Eventually, slayers would become a more general term for anyone willing to pick up a blade and kill some vampires. Later on, they would become large, roving bands of survivors scavenging the wastes for supplies and slaying any ghoul, vamp, or beast they came across. Some would even gun down a complete group of strangers off the smallest suspicion they could be vampires.
