d20 Chatrealm - Series 2
The Shadow is the colloquial term used for the barrier between dimensions, but it can also refer to the portal in which beings from other dimensions into our plane.
Though it is unknown exactly when the first coinsurance of Shadowkind entering our dimension, the first official report occurred in 1947. Though widely thought to be a UFO related incident in New Mexico, this was actually the first occurrence of Shadowkind entering our dimension. This incident would later be one of the pivotal events that would cause the formation of Department 7.
ScienceAlthough the exact nature as why this phenomenon occurs, the current speculation is it has to due to the resonant frequency of both dimensions overlapping at specific moments in the space-time continuum. Thought the physical manifestation has yet to be recorded on camera, eye witnesses describe this phenomenon to have the appearance of abnormally dense fog or swirling pools of black mass with the constancy of tar.
Effects of The Shadow
Shadowkind that have come into our dimension report that they have no memory of how or why they entered our dimension. The being remembers their name and core beliefs, but forget everything of their previous existence, such as politics and geography. It has yet to be determined why this is the case, but it is speculated that while the being is realigned within this dimension that the part of the brain that deals with factual information is effected.
There are currently no recorded incidents of a being from our dimension traveling through the Shadow and returning.