Shadeling

Shadelings are bizarre and dangerous denizens of the demiplane of Shadow. They are often compared to doppelgangers, for they seek to mimic the forms of others and then kill them. In their natural form they are flowing, sentient shadows about the size of a human, but irregular in shape.

Combat: Shadelings possess the power of duplication. The shadeling engulfs its victim's shadow if the unfortunate fails a saving throw vs. breath weapon. Once this is done, the shadeling takes the victim's material form. The victim's weaponry and armor are duplicated as well, although duplicated magical items cannot be magical themselves. The swaddling immediately gains all the physical abilities of its victim, including hit points, Armor Class, and special physical attacks and defenses.

Once a shadeling has taken a material form, it attempts to slay the being it has duplicated. If it manages to do so, it remains in its new form for 2d10 days. Then it returns to its true form and must find another victim.

In its true form, the shadeling cannot be physically harmed and is unaffected by most spells. Both light and darkness spells have a 5% chance per level of the caster to destroy the shadeling, and the continual versions of these spells have a 10% chance per level of the caster. Dispel evil and protection from evil spells affect shadelings normally, and a shadow walk spell cast upon them destroys them automatically, as does the sunray spell. A holy word uttered at a shadeling in physical form causes it to revert to its true form, while a holy word uttered at a shadeling in shadow form banishes it to the demiplane of Shadow. If killed while in the form of some other being, the shadeling returns to its shadow form, but it loses the power to duplicate for a full day.

Note that although they may resemble undead, shadelings cannot be turned by priests. However, they are elemental beings and are subject to spells and other magic that affects other creatures from the Inner Planes.

Habitat/Society: Shadelings seem to have only one purpose; to duplicate living beings and feed on their shadows. Although they are found in groups of up to 10, they don't appear to work together to accomplish any goal. Indeed, they will all attempt to steal the form of a single being, without any sense of strategy or hierarchy. Sages speculate that they exist in numbers only because they escape the demiplane of Shadow together, probably through elemental vortices.

Ecology: Shadelings have no natural place in the ecology of the Prime Material Plane, and nothing is known of their role in the demiplane of Shadow. However, various wizards have found some uses for these creatures in the workings of magic: Any mirror that has been prepared by casting enchant an item and permanency spells on it, and which is subsequently engulfed by a shadeling will instantly become a mirror of opposition.