Akara: Lands of Chaos
“Psionics is a source of power that originates from within a creature’s mind, allowing it to augment its physical capabilities and the minds of others.
Psionics indirectly originates from the Far Realm, the place on the outskirts of the Plane of Chaos where the demented entities known as the Ancient Elder Gods came from. It is outside the bounds of the known multiverse. The Far Realm has its own alien laws of physics and magic. When its influence extends to a world, the Far Realm invariably spawns horrific monsters and madness as it bends reality to its own rules.
As the laws of reality twist and turn, individual minds can awaken to the cosmic underpinnings that dictate the form and nature of reality. The tumult caused by the incursion of the Far Realm creates echoes that can disturb and awaken minds that might otherwise slumber. Such awakened creatures look on the world in the same way creatures existing in three dimensions might look on a two-dimensional realm. They see possibilities, options, and connections that are unfathomable to those with a more limited view of reality."
Unearthed Arcana: Psionics & the Mystic