So, I've been thinking about my post-apoc fantasy setting. Incidentally, for now, I am calling it Aurelian.
One of the bits is the presence of psionically-gifted humans. Another is the presence of "monsters." After much thinking, I think I can tie many of these elements together fairly neatly.
It all starts with a virus....
The Psion PlagueSo, many years ago I read Barbara Hambly's Those Who Hunt the Night. It's a really great vampire novel. One of the central conceits is that vampires are humans who have been infected by a virus. The virus gradually replaced all the DNA in the human's cells, radically changing them. In addition to the standard strengths and weaknesses of vampirism, the virus also gave them psionic abilities (vampires' famous mesmerism). Apparently, virus-spawned psi powers were actually a popular theory in early 20th century medical journals (though, obviously, not one that ever gained traction).
I've taken that tack with my psionics. A virus entered the human population sometime around the collapse of civilization. Given the poor records of that time, it is hard to know if it was before, after, or the cause of the collapse. Of course, considering how widespread the virus is, it would almost have to have started spreading while intercontinental travel was still common
This virus affects everyone. A small number prove incompatible with the virus and die from complications. As this incompatibility is genetic, and the virus affects people at the onset of puberty, those who die are largely weeded out in a few generations.
The majority of people, over 70% of the population, get very sick when the virus activates (again, that would be the onset of puberty for those exposed as children, as all people in the current setting are). Cramps, low-grade fever, hallucinations, and severe gastrointestinal distress are the typical symptoms. In the Kingdom of Zion, this is referred to as the Ordeal of Jacob. In the Confederacy of the Great Lakes, it is known as The Wracking. It lasts for three days, and then passes. The infection has not been driven out of the body. Rather, it has convinced the body to stop fighting it. No further symptoms are evident.
For a small, but not insignificant, fraction of the population, they come out of The Wracking changed. They have gained psion abilities. For anyone familiar with ShadowForce Archer, these are nearly a direct copy of those abilities, with a few extra added on. For those not familiar with that type, it covers a wide range of mental abilities, loosely grouped together. In game mechanics terms, you take a feat to gain access to a family of abilities. Each ability within that family is represented by a skill, which you must then put points into. In game reality terms, think your basic types of superpowers for a "street level" supers setting.
This virus really only affects humans. However, the virus also interacts very interestingly with other viruses of the Lyssavirus genus. That would be rabies, among others. The viruses merge, creating new and terrifying effects. There are two primary strains of this super-virus: Lycanthropy and Vampirism. Both strains are capable of infecting any mammal, and can be transmitted through fluid exchange (e.g., blood contamination, bite, sexual intercourse).
Werewolf? There Wolf!
Lycanthropy has the effect of transforming the victim into a larger, stronger, and more bestial version of himself. Muscle mass increases, the jaw and the teeth lengthen, nails grow and thicken into claws, and the skin thickens to a rough, hairy hide. (Do note that this is a one-time and one-way transformation. Unlike the mythical werewolf, the victim does not gain the ability to change back and forth between a bestial and non-bestial form.) The victim tends to become very violent and aggressive. The victim also becomes ravenously hungry, with a particular taste for flesh and blood (even if the victim is a herbivorous animal and cannot digest meat). As an additional benefit, though, the victim's senses become extremely acute.
As terrifying as these changes are, they are not the most significant. As the virus inhabits the body, it also grants the body exceptional recuperative powers. A lycanthrope can recover from nearly any injury at a truly remarkable rate. The only wounds which will kill a lycanthrope are those which destroy the brain, destroy the heart, or completely sever the connection between them (typically through decapitation). Merely wounding either the brain or heart is not sufficient, either. A typical sniper bullet through the skull will only incapacitate a lycanthrope (though, naturally, this is often enough to follow up with a more thorough method of destruction). There is one exception, however. Silver, well known for its antiviral properties, disrupts the regenerative process. A silver weapon will cause a wound that will not heal. An injection of colloidal silver in a newly infected individual has a chance of reversing the transformation process. Once the process is complete, however, all the injection will do is prevent any regeneration, allowing the victim the release of a quick death.
One final note of interest is that the virus creates a peculiar telepathic connection among nearby infected creatures. Between human victims, this presents only as a crude form of communication, allowing a group of lycanthropes to act as a unified pack. Infected animals, however, are nearly wholly subject to the will of infected humans. They will follow the mental commands of their master, even unto death.
The virus took on the name "lycanthropy" due to its obvious similarities with the mythical werewolf. The bestial form of the victim brings to mind human-animal hybrids. The minds of the victims are often not used to the radically enhanced senses, causing them to shy away from bright lights (making them largely nocturnal) and strong odors (such as garlic and wolfsbane). The "curse" is transmitted most often by bite. The victim will go on a violent murderous spree, typically marked by cannibalism. Lycanthropes appear to shrug off most injuries, except for the legendary silver bullet. However, it is important to note that there is no supernatural component to this disease. It may also be worth noting that there is no connection between a lycanthrope's condition and the phase of the moon (other than the fact that a full moon provides excellent light for hunting).
Sparkling Is NOT an Option
Vampirism is remarkably similar to lycanthropy in many respects. It involves significant regenerative capabilities, which can be undone by silver, decapitation, or destruction of the brain or heart (the classic wooden stake is useful here, but not necessary). The victim becomes ravenously hungry, with a taste for blood. The victim develops exceptional senses, and tends to avoid sunlight and garlic as a result.
There are some significant differences, however. In the vast majority of cases, the victim is actually referred to as a "ghoul." There is no growth or other acquisition of bestial traits. The victim's higher brain functions are nearly entirely eradicated, though. He becomes a violent, mindless, voracious beast. The regenerative effect is also considerably slower in ghouls than in lycanthropes, though they do gain a near immunity to pain. This tends to result in ghouls walking around with a variety of injuries, some apparently mortal, without significantly slowing down. This is how the disease presents in animals, and in normal humans.
Psions, however, have a very different reaction to the disease. This is where the vampire comparison comes into play. When a psion becomes infected, there is no apparent physical change. They can, in fact, move among uninfected humans without drawing much attention at all. The psion also retains all of their intelligence and memory. They do still develop a strong taste for blood, and a tendency towards violence, but they are able to exert some control over this (the same sort of control an alcoholic has to avoid a drink, admittedly, but enough to not go on a rampage). Additionally, their psion abilities get remarkably reinforced, granting them new and amazing levels of power. Among other things, they are able to use their psion abilities to boost their own regeneration, closing even near-fatal wounds in seconds.
Vampiric psions also come with another advantage. In the same way that lycanthropes are able to command the service of infected animals, vampires can command the service of ghouls. They have some ability to enforce this command over other vampires, but it is a battle of wills, and never as thorough as their command of the mindless hordes.
Again, note that there is no supernatural effect behind the abilities of a vampire or ghoul. Holy ground or holy symbols will do you no good. They avoid sunlight because it is hard on their eyes, not because they will burst into flame. They are not able to change into bats or mist or anything of the like. They may be ageless, as a side effect of the regeneration, but no one has allowed a vampire to live long enough to find out. They do not burst into a cloud of dust when killed, and they most certainly do not sparkle.