The Pseudo-Undead are living breathing humanoids who resemble, and strive to mimic, the undead. Their physical and cultural evolution has aligned itself with the traits of the undead so as to shroud and protect themselves with the myths and legends of men. The pseudo-undead possess some of the physical traits of those legendary undead monsters they resemble, but none of the inherent traits of undeath, they are not immortal, and they have no supernatural powers save those they learn or acquire through enchanted items.
The Pseudo-Undead can be broken into two broad groupings, those of mixed human-humanoid-monster heritage who strongly resemble a given type of undead purely coincidentally, and those rare undead obsessed humans and humanoids who descend into a sort of madness. The first category knows full well that they aren't true undead, the latter thinks they are of the undead, or at least on the cusp of becoming undead. The Mongrel type are generally members of Pseudo-Undead families while the insane type are usually solitary, and both types of Pseudo-undead avoid the genuine article if at all possible.
Pseudo-Undead mimic corporeal undead for the most part as they cannot fly and are generally discernibly corporeal themselves. A few mimic wraiths or even ghosts, but they generally have to avoid being touched to pull off the illusion. Those corporeal undead that are fleshless or skeletal are generally mimicked by beings that are naturally (or by enchantment) transparent.
Though only resembling true undead the Pseudo-Undead are often powerful opponents themselves; Pseudo-Vampires are strong, long lived, and generally great sorcerers; Pseudo-Zombies are impervious to pain, able to sustain great injuries. and possessed of clawing and biting attacks; Pseudo-Ghouls often use paralytic poisons, and mans horror over their corpse eating habits to terrify opponents. Pseudo-undead, while providing a way to force adventurers to change up tactics, should definitely be considered as monsters in their own right, with an individual history, or group history, and with their own desires and goals beyond simply playing a trick on our hero's.
Imagine a series of small duchies located on a rarely visited mountain range deep in the heart of a kingdom. These Duchies are presided over by dukes and duchesses who've held their positions, and their youth, for so long that the myth of the vampire has been evoked to explain the circumstances. the duchies are embroiled in a 200 year long cold war with the largest of the group. Hero's are brought in on the side of the allied duchies to commit acts of espionage against their foe only to find out that the legends are true, except of course for their target. Â The ageless vampires are fighting to keep the war long and drawn out so they can endure the sorcery of their mortal opponent until his long long life comes to an end. Do they complete their task to prevent the bloodshed of an all out war? Do they side with the mortal mimic against the depravations of the vampires? Do they play both sides, bring the truth to the people, and incite a revolution?
Imagine a swamp thats home to bands of inbredÂ mongrel-men with powerful sturdy bodies who feel no pain, continue through great injury, and hunger for the living. No cleric can turn these strange zombies, and due to a troll somewhere in the family tree they regenerate (if slowly)....