The term "jyse" refers to a pocket of willpower that Focus users can tap into or channel their Focus through. They should not be confused with the creatures called Jyse, which are believed to be created by these pockets.
As the Overseers explored the depths of the universe, they discovered pockets of willpower through which they could channel their Focus for astoundingly powerful results. They called these pockets "jyse", or "loci". They believed they were centers of the fundamental will of the universe.
Willpower is believed to be the most fundamental force in the universe. Many Focus using races believe the reason for existence is that concentrations of willpower became dense enough to will themselves into existence. They became the first matter in the universe. Eventually enough pockets of willpower condensed into actual matter that the Universe formed. However, primordial pockets of willpower that were never quire dense enough to will themselves into existence still remain. These pockets of willpower are the jyse.
There is, however, an alternative belief. In the beginning there was nothing but these pockets of willpower, each contending with the others by their very nature. Eventually they formed themselves into the first sentient beings in the universe. Their conflict, however, continued, with each guiding an aspect of existence as we know it.
These Primordial Wills, god-like in their powers, allowed their will to flow into their creations. Eventually, they faded, some draining themselves of their own existence, while others simply became mortal beings. Those that drained their existence, however, left "husks", the dead shells of what they once were. Those shells are believed to be the jyse.
It is rumored that some jyse have their own sentience. These Jyse are incapable of willing themselves into physical existence, and yet are unwilling or unable to fade into a lack of sentience. These creatures are terrifyingly powerful, if they can find a Focus user who is receptive enough to tap into or channel their will through them.
(See the Jyse (race) for more information.)