The khert /xert/ is the vast and invisible spectral plane within which and on top of which the world of Unsounded exists. It effects and defines all living and unliving matter, holds all natural laws, and in many ways guides destinies. Pymary works by giving instructions to the khert.
The khert exists only in the vicinity of Kasslyne. Deep underground, it becomes thick. A few hundred feet above the surface or away from its shores, it becomes thin. Either makes pymary difficult. Traveling beyond the khert's influence is fatal for an unaccustomed human. The khert also does not extend into senet beasts or First Materials.
Difficult to understand, the khert has been studied by scholars and wrights since the beginning of history. The khert seems composed of contradictions; it is at once capable of being mapped and bound to correlating space in reality, and yet it is constantly in motion; it solidly defines the dimensions of all space and objects in reality and yet it can be dispersed with a breath of air; it is at once hostile towards foreign energies and yet receptive and protective of the faintest psychic pulses whispered into it.
In spite of these observations, scholars have long classed the khert as a logical and predictable force, allowing them to program spellwork into it and make the practise of pymary safer.