Magic in Tariek Rough Collection
The Pulses of Magick

As the raw, but tainted primordial energy bleeds into our realm from the Void, it seperates, like light through a prism. As it splinters, and becomes what magisters refer to the 'Pulses' of Magick. These seven different sorts of flows and currents, these are what feed magisters. They are named for the elemental tie they each have, and are commonly known by a name for their color as well.

Every race reacts differently to Magick, and though every race can produce magisters, some are more common than others, and each seems inexplicably tied to a particalur race. That is not to say that one cannot end up being a practitioner of any given Pulse, just that your race makes one in particular far more likely than the others.

World Codex