After The Fold, many sentient beings were infused with magical power, theorized to be a sort of industrial run-off from the civilization which caused The Fold in the first place. This power manifests in many ways, with some gaining strange abilities, odd new forms, or bizarre insights into the new world. A small number of sentients became Powerful Beings.
The distinction between a Powerful Being and someone who is capable of mundane magics is sometimes a little difficult to determine, but generally can be understood by examining a beings relationship to the means of magical production. All Powerful Beings occupy space within the metamagical folded dimensions that allow them exclusive access to the sources of magical energy, and act as direct funnels between those sources, and everyone else. In other words, Powerful Beings are the defacto owners of the source of all magical energy flowing into our world, while other magical beings are merely recipients of the energy.
Recent research that suggests the magic itself is generated by emotional energy has been rejected in favour of a Comun-IT funded study which instead suggest commerce generates magic force.