Psions are those who follow The Way. These are the practitioners of psionics who make the most extensive study into it. All of the major cities have psionic academies where psions go to study. It is considered a good idea to study and teach in as many academies as possible. Templerates also typically have psions in their employ.
Psionics has been in Athas since the beginning of the Blue Age. It was discovered by the Rebirth races after leaving the area of the Pristine Tower.