Most faiths speak of the final treatment of the dead; rituals that must be followed to assure that the souls will pass on to the afterlife, and the bodies will rest quietly in the grave for nature to reclaim. Often there are dire warnings about what might result if these religious rules are not followed; often the warnings alone prove enough, and the dead do indeed rest easily.
Sometimes even the simplest parts of ritual are not given to the dead, however; a drunken pauper too poor, too reviled to have even a brief prayer said over him by the priests who look after the dead before being buried in an unmarked grave, naked and without even a lone copper coin to pay his fare across the darkened river into the twilight realms. It is from these poor souls that the Unclean Ones arise.
Physically, the Unclean Ones are difficult to tell apart from the creations of a necromancer; their bodies are often rotted, with putrefied flesh clinging to bone and a terrible light glimmering where once there were eyes. Often the only outward sign that such a thing is one of the Unclean is that it lacks even the rotting rags that zombies wear; no funeral garb adorns these pathetic creatures as they shuffle awkwardly along. They exude a disquieting odor, the stink of rot mixed with the scent of the grave-earth they clawed free from, and often they produce an unwholesome wheezing sound as they unthinkingly try to draw breath as if still alive.
An Unclean One, once arisen, seeks but one goal: the items it needs to pass truly into the afterlife. While this does not always lead to violence - wise gravetenders keep a spare set of funeral clothes and a few spare coins in the pauper’s corner - an Unclean One will not hesitate to attack someone to claim their clothes as funeral garb, or their coins as fare for the toll to cross the river into the afterlife. If freely given these things, the shambling thing will shuffle away to the grave from which it arose, draping the clothing as best it can while it burrows back to the place it belongs. If resisted, however, the Unclean One fights desperately, as without the things it seeks only oblivion awaits it should it fall.
The Unclean Ones are perhaps among the most pathetic forms of the undead, and any priest with a decent degree of training can realize what the thing seeks; only the most heartless would deny the poor thing what it needs, even among the servants of the dark gods, for the Unclean Ones cannot be made to serve.
-The Unclean Ones are not a form of undead that can be commanded or repelled by divine means; their soul inhabits the rotting body and serves to animate it, rather than any link to an external power.
-If given what they seek, the Unclean Ones will return to their grave as swiftly as possible to continue on into the afterlife.
-The Unclean Ones will attack the living if they happen to be in direct possession of whatever the creature seeks, and unwilling to relinquish it to the creature; their fingerbones, often broken into jagged points from clawing to the surface, can be quite dangerous.
-Destroying an Unclean One condemns the soul therein to oblivion, which most faiths are likely to frown upon.
-The Unclean Ones only arise when a corpse is buried without any traces of an attempt at last rites; often this means being buried without clothing and without coins, but depending on the religion it could mean any number of things. Inevitably, they seek the simplest things which they were denied.
-Unclean Ones are appearing with distressing frequency from a city’s graveyard. Someone working there is stripping everything from the dead before burial, preventing them from resting.
-A follower of an obscure faith, buried in accordance with local traditions, has arisen as an Unclean One. What does it seek in order to be able to rest? How much damage will it cause in the seeking?
-The PCs have recently had to inter a loved one or perhaps a member of their party, and ensured that they were buried properly. Why, then, has an Unclean One bearing the recently departed’s features arisen? Is it truly an Unclean One, or is something more malevolent afoot?
-One of the items required for burial is a crystal disc etched with a holy symbol, to be traded to the guards of the afterlife in exhcange for passage. Unfortunately, the only person who could etch the discs was just buried with the last of their stock. Someone needs to find a supply of the discs to last until another crystal-etcher can be found and hired.