In general the world of Myaasia has an overabundance of magic. Raw magic in all its forms is unusable, so the limiting factor in magic use is the skill of the wielders to focus it, else the effects would be totally chaotic.
If all the power were evenly divided, everyone would live in an area with too much magic, causing total chaos. Luckily, more than three quarters of the total magic power of the world is locked in the Essaence streams, thus making the other areas livable.
These Essaence concentrations are mainly of two types:
The lesser are nodes where magic raises to the surface from below. They are relatively low power, though the power of even a small node dwarfs that of any wizard.
The greater are streams that flow from one place to another. Navigation past the streams is practically impossible. Only the Navigators and maybe some other individuals can bypass them, all others must go around. These streams split the world into small pieces and make long distance travel very hard.
Normal effects for entering a node or approaching a stream include everything from polymorphing to increased or decreased abilities to death. Though those able to channel the chaotic magic can lessen the impact.
Some skillful masters of magic can call upon this chaotic magic and channel it to themselves or away from themselves.
There are times when a region experiences a high concentration of magic. These are called Essaence storms. Depending on the severity, they can range from strong storms to random transmutations to total devastation of an area. These storms are most common close to the streams.
There are more than 800 known nodes and more than 200 known streams in the western hemisphere.