Potential
Interwoven throughout the fabric of the inhabited worlds is a force of nature known as the Potential. It is by harnessing this Potential that certain species of intelligent being are able to perform acts of what we might otherwise call magic. Each member of those species possesses an organ called the auní which serves as the means for interaction with the Potential. In those with stronger auní the ability to make use of the Potential is stronger, but the degree to which they are affected by it is commensurately stronger as well. Those rare individuals without functioning auní are referred to as unsensed (analogous to blindness vis-à-vis sight or deafness vis-à-vis hearing) and cannot interact with the Potential at all: they are both entirely incapable of using magic and entirely unaffected by it.
Behind the Scenes
The term 'Potential' was introduced as a placeholder name; it is up to a future Move to confirm it or to replace it as that Player sees fit.
The Potential is envisioned as functioning as a natural force, akin to electromagnetism, which obeys scientific principles and which has always existed, but which has taken centuries of study and experimentation to learn to harness. There is as yet no determination as to the level of advancement in the use of the Potential in the main game world.