'Shadowlings, Are They Misunderstood or the Ultimate Threat to Our World.' The dark ages were called this for a reason. This was when the Shadowlings nearly covered the realms in darkness and plunged everyone into terror and despair.
The Shadowlings are one of the realms oldest creatures coming from the time when darkness and light first separated into being. The darkest points of the realms were said to become these creatures. They existed alongside the creatures of both light and dark from the beginning.
Then at some point, high-ranking angels and demons decided to make servants of the Shadowlings enslaving the creatures' massive power to themselves. Sometimes using that power to do despicable things while badly mistreating the creatures that gave them that power in the first place.