Ghost Plague

A Ghost Plague is a classification of especially dangerous and powerful ghost. There are many other names for this kind of ghost, "living curse", "viral soul", "Chain-Letter Curses", and "nensha-shi" among the more common. There are three main criteria that a ghost must fall under to be considered a Ghost Plague:
1) The ghost must haunt an item that can be copied and also be able to haunt the copies of this item made in its presence.
2) The ghost must be powerful enough to at least permanently affect its victims in some way (mentally or physically).
3) The ghost must be able to gain power over time.

A Ghost Plague lives to spread. They haunt anyone who comes in contact with its item, slowly gaining in power until that person pacifies it or dies trying. In most all cases, the ghost is pacified when the person makes a copy of that ghost's item and passes that copy to another person. The danger in this is that the more people that pass the item along, the more chances there are for many more people to become haunted by the ghost. Luckily, many of these items are fairly easy to copy, such as a series of glyphs telling the ghost's story, or a simple item related to the ghost (a key for instance). Also the amount of time before the ghost becomes powerful enough to kill or disable its victim is usually several months, giving the victim plenty of time to make the copy and spread it.

Even after the ghost is pacified, it may haunt any of its previous victims indefinitely, though they will no longer be able to harm that person in any way. The most extreme case in Felarya is the ghost of a wizard who was able to cast an invulnerable sphere in a predator's stomach to save himself, only to eventually succumb to starvation himself after weeks of rationing his food. The item is a simple glyph carved into a piece of bamboo and painted in with some blood. The ghost himself is able to kill his victim after twenty days of gaining power, over which time he sends nightmares and visions of being digested, along with visions of the item to be duplicated (based on the focus for his invulnerable sphere spell).

Often these spirits are destroyed by especially powerful exorcists (or just plain destroying their haunted items and killing off the haunted before they can make more copies), but they can occasionally destroy entire villages.

There are rumors of ghost plagues on other worlds, even one that is powerful enough to kill in one week.

(Idea based on the Ringu stories, Especially the last part, I've modified it enough to fit in the Felarya universe, though.)

I think this is an interesting and original idea
Better think about two times when you buy an unknown item XD

Sounds a bit like a chain letter.

Haar wrote:

Sounds a bit like a chain letter.

Hence on of it's nicknames. The main difference is that a Ghost Plague has a powerful intelligence behind it that enforces it and attempts to guide the passing of the curse to achieve the ghost's goals.

In some cases, the ghost's attitude toward someone becomes drastically different once the curse has been passed on, ranging from annoyed disinterest to warm affection. In any case, the ghost can do no harm to those it haunts unless they are under the curse.

Often, cults tend to spring up around a ghost plague, with cultists using their copy of the cursed item as a kind of holy symbol.