Interlife Earth
Interlife Earth is an alternate Earth distinguished principally by distinctive conditions of its afterlife. Many of those who die on Interlife Earth become ghosts, especially those who die under unusual or emotionally charged conditions. This, in itself, is true of many magical Earths, but the ghosts of Interlife Earth are a little different from those of other worlds. They come in a number of special varieties, and spend most of their time in a place called the Spirit World, made up of "ghosts" of long-vanished but still-remembered buildings and places. However, they can come to the mortal world through mirrors, and in fact must spend some time there to maintain their ghostly existence.
As with most of the names of alternate Earths in the Wongery, "Interlife Earth" is not a name that would actually be used by residents of the world. They do, however, use the word "interlife", to refer to the state of being a ghost—ghosts of Interlife Earth do not seem to be immortal, so ghosthood does not constitute a true, permanent afterlife, being more of an "interlife" between mortality and whatever ultimate fate, if any, lies beyond.
Places of Interlife Earth
"Interlife Earth" actually consists not only of the planet Earth itself, but of the Earth and a few associated planes closed to most mortals, but readily accessible to ghosts: the Spirit World, and the Gap.
Mortal World
The Mortal World is where humans live before their deaths, and overall bears a close resemblance to True Earth. Most humans do not know about the existence of ghosts, or perhaps believe in them but have no proof of their existence and no knowledge of the details of their types and society. While living creatures can travel freely about the Mortal World, ghosts are confined to specific areas within it, known as haunts.
Haunts
A haunt is a location within the Mortal World that ghosts may enter. Haunts are generally created by traumatic or tragic circumstances; in general, when a person becomes a ghost, the place where he died becomes a haunt, though rarely haunts may arise due to other circumstances. The size of the haunt depends on the event that led to it; if a single old woman dies alone and becomes a ghost, her room may become a haunt, whereas in a war an entire battlefield miles across could potentially become haunted.
Unless two haunts are physically connected, a ghost cannot travel directly between them. For a ghost, across the boundaries of a haunt is not the mortal world, but a vast expanse called the Gap. The only way in or out of a haunt without entering the Gap is through a mirror; each mirror in a haunt connects to a corresponding mirror in the Spirit World, and a ghost may enter one mirror and emerge from the other.
Spirit World
While the Mortal World is the domain mostly of ghosts, the Spirit World is the home of ghosts, accessible by mortals only to those who bear the ability of ghostwalking. Most ghosts spend most of their time and make their permanent homes in the Spirit World, though all ghosts must visit the Mortal World from time to time to maintain their existence.
The Spirit World is a complex amalgam of vanished sites and places from the Mortal World of the past. Not every demolished building or paved patch of greenery ends up in the Spirit World; the exact criteria aren't clear, but certainly any location or structure that was particularly famous, or remains well remembered after its destruction, has its counterpart in the Spirit World; all the Seven Wonders of the Ancient World, save the still-extant Pyramids, are there, as well as the Library of Alexandria, which remains in active use (and has its venerable texts supplemented by many more modern books). Of course, many more modern buildings also exist in the Spirit World, Some entire cities exist in the Spirit World, cities which were demolished wholesale such as Pompeii and towns like St. Thomas that in the Mortal World are now underwater, but most of the buildings in the Spirit World exist there individually, without their former neighbors or surroundings, and join with neighboring structures or with exterior areas in seemingly random ways, with doorways connecting the shadows of structures originally far apart geographically and chronologically. The Spirit World also contains some tracts of land from demolished terrains, including more and more expanse of jungle as the rain forest in the Mortal World shrinks.
The Gap
If ghosts try to travel beyond the borders of haunts, they do not encounter an impassible barrier. Rather, they enter a vast and perilous expanse of uncreated notions. This place, or non-place, goes by many names; some call it Tohubohu, some the Abyss, some Ginnungagap—or the Gap, for short—, this last of which has become its most common name.
The Gap is made up of the inchoate shadows of things not yet created and the aborted vestiges of creations left unfinished, of dreams and possibilities and of primal emotions. It is not so much a physical place as it is a metaphysical state, though for ghosts within it it seems like a place for all practical purposes, and an enormous one at that. Wise ghosts avoid passing through the Gap, not only because its lack of static landmarks makes it easy to get lost there but because it is filled with nightmare entities, terrible phantasms born of the fear and apprehensions of the living and the dead.
It could well be that far off across the yawn of the Gap are entrances to other worlds and planes, unknown to mortal and ghost society. If so, however, there are few who would be willing to brave the dangers of the void to find them.
Interlife ghosts
Not all mortals become ghosts when they die; the manner of death seems to be a factor, and particularly traumatic or otherwise noteworthy deaths are more likely to result in the creation of ghosts, but some characteristics of the deceased's personality also seem to be involved, and particularly strong-willed decedents may become ghosts even if they die of old age peacefully in their sleep. Ghosts may or may not remember their former lives; those with no memories of their lives and no knowledge of how they attained their current state are sometimes called the Blissful Dead, though this is in reference to the old adage that "ignorance is bliss" and not to the demeanor of the ghosts in question, who can often be bitter and angry and anything but blissful.
There are six main varieties of ghost on Interlife Earth; which type a particular ghost becomes depends usually on the circumstances of their deaths. The following enumeration orders the ghosts according to their frequency, from most to least common, though the difference isn't great.
Specters
The common cause behind the formation of specters isn't entirely understood, and it may be that they're simply the "default" kind of ghost if none of the other types occur. Specters usually appear largely as they did in life, although they have the ability to alter their appearance slightly, to the extent of changing clothing and other accouterments. Some specters develop the ability to change their forms more dramatically, even to the extent of splitting off reshaped parts of their own matter into independent objects; this is one of the few ways new objects can be created in the Spirit World.
Shades
A shade is usually formed by a death by violence, though such deaths may also result in the formation of specters or apparitions; for whatever reason, death by sharp bladed weapons such as axes and spears seems more likely to result in a shade, though there are certainly other factors involved. Shades appear as they did at the moment of, or just before, their deaths, but unlike specters they are fixed in that state and unable to alter their form even to the extent of changing clothing or removing the wounds that led to their deaths.
Wraiths
A wraith is formed by a death that for whatever reason had particularly significant repercussions on later events, or is connected with paranormal matters—those killed by ghosts, for instance, often, though not always, become wraiths. A wraith is an amorphous glowing (or, more rarely, shadowy) figure, sometimes blobby and amorphous and sometimes humanoid in form, though even the latter almost never have recognizeable facial features. Wraiths are very difficult for mortals to tell apart, though ghosts learn to perceive the subtle differences between them.
Phantoms
Phantoms are usually created when a person is killed in such a way as to completely destroy, or at least seriously damage, the body—in explosions, for instance, or if a person is crushed by a very large object. Phantoms have no form of their own, but are able to possess objects and, for limited amounts of time, creatures, taking them over and granting them motion. If a phantom spends a large amount of time in a particular object, it can adopt that object as its permanent host, gaining greater control over it, and the ability to heal damage to it, in return for an inability to transfer itself into other objects.
Apparitions
Apparitions are usually formed from those dying in extreme anger, though in rare cases they may arise from other causes. They appear vaguely humanoid in form, though usually much better defined than wraiths, and, unlike wraiths, they are often easily recognizable to those who knew them in life. Apparitions, however, have their forms twisted and augmented in some way, the details varying by individual but always in manners that increase their fighting potential; common features of apparitions include horns, spikes, claws, and sharp rending teeth, and they may have tails or extra limbs.
Ghouls
Ghouls are rare ghosts who retain control over their physical bodies, albeit not necessarily over the processes of decay and putrefaction. They frequently resemble animated rotting corpses, perhaps missing limbs and very clearly dead; some rare ghouls may manage to keep themselves fresh and be almost indistinguishable from the living, but even then their glassy eyes may give them away to the observant. Ghouls, having a physical form, can be physically damaged, but they can also heal the damage to their bodies, although they can do so only by eating flesh. The flesh need not be either fresh or human, but some malevolent ghouls do enjoy ripping organs from living victims.
Ghostly society
The ghosts of Interlife Earth have no formal government, but in practice there are individual ghosts who have dominion over specific parts of the Spirit World—and those haunted areas of the Mortal World that connect to them. While they do not necessarily have formal titles (though some may grant themselves such titles), these spirit rulers may have enough other ghosts loyal to them to exercise significant amounts of power. Aside from that, society in most parts of the Spirit World is fairly anarchical. The Spirit World doesn't have much of an economy; given the difficulty of manufacturing objects, there is no fixed coinage throughout most of the Spirit World, reducing ghosts to engaging in barter when they need to trade, but since ghosts have no real needs for survival other than occasional visits to the Mortal World they don't need to trade for much anyway.
Many ghosts disdain the society of other ghosts altogether, either remaining in their haunts in the Mortal World or wandering empty tracts of the Spirit World. Some ghosts make it their mission to try to find new ghosts and introduce them to the larger ghost society, but not all ghosts are happy to be so integrated.
Other creatures of Interlife Earth
Besides the ghosts and the myriad weird monsters of the Gap, there are a number of other paranormal creatures found in Interlife Earth. One of the most mysterious and most dangerous—to mortals, if usually harmless to ghosts— is the slasher, apparently a human somehow changed by some mystical process and made into a perdurable and homicidal killing machine with special powers. Another well-known entity is the ghostlight, small glowing balls of light apparently born from rare gestalt manifestations of multiple ghosts called phantasmagorias. Also, certain extinct creatures seem to have given birth to "categorical ghosts" representing not individual organisms, but entire species or taxa, including the passenger, a remnant of the now-vanished passenger pigeon, and the ancient necrosaurs, shadows of the long-dead dinosaur.
Eidolons
Perhaps the most powerful entities of Interlife Earth, or at least among the most famous among the ghost population, are eidolons, beings which were once ghosts but have somehow transcended that status into apparently immortal forces, which no longer seem to exist in any normal way as single, monolocal beings, but which can be summoned into existence in various ways, or may appear in response to certain triggers and conditions. Some eidolons, such as the infamous Bloody Mary, are fearsome and dangerous, but others can be helpful or useful.