There is a certain intrinsic perversity which quickly becomes apparent when one spends any time studying or interacting with the denizens of the Borderlands and the territories which lie beyond.
While there is little which can be definitively stated which could be applied to all such beings, they can be, perhaps profitably, divided into three broad groups.
The greatest amongst them are beings of elder chaos. The forms and motives of such alien entities are destined to remain nearly incomprehensible to humanity. In terms of power, they more closely resemble gods than mortal creatures. The very environment seems to bend to satisfy the merest whim of these beings without apparent effort on their part.
The next tier of intelligent denizens are, while still possessed of power hardly approachable by our kind, and tending to serve as the royalty of those realms, are at least somewhat more comprehensible. These beings seem to embody concepts or categories which hold strong resonance in human minds, leading to debate, (at least among human scholars) regarding which direction such thematic influence originally flowed. If anyone has dared ask the creatures themselves, they have failed to return and report the answer.
The final group are those creatures which comprise the closest thing which those territories have to common folk. While far closer to humanity in terms of longevity and power than their immediate masters, they are in some ways even stranger. This category seems the most mutable, their physical forms and their minds seemingly influenced by thoughts and especially the emotions of nearby creatures. This effect seems particularly strong when they are encountered singly or in small numbers by lone humans who are lost or unaware of the nature of the Borderlands, such that it probably accounts for many tales of both monstrous ogres and irresistibly beautiful nymphs and satyrs encountered by our ancestors in primal woods and lonely glens of antiquity.