Sometimes, too much manipulation of magic can have adverse effects on the energetic condition of the realm.
In order to preserve the tranquility of the energy flows, nature channels these disruptions into specific points, creating temporary Nexi of raw elemental power.
The Nexi energies are, for the most part, self-contained and entirely self-sufficient. They create themselves when needed, and fade away automatically once the crisis has been averted. For such a thing to occur, however, there must be intelligent life fueling it — and, indeed, there is.
The Nexi are sentient creatures, composed of raw elemental energies. They represent the four basic elements of nature: Fire, Water, Air and earth.
These four Nexi seek to fix disturbances in the layout of the energy lines. To do this, the must borrow bits and pieces of life from other organisms, using them as filling and binding agents.
The best source of life energy is from a person, and the Elementalists know it. In the rare occasion that one should find such a person, I would not hesitate to kill an Elementalist on the spot.
Be warned, traveler: While the knowledge that you are near an Elementalist is unmistakable, it is exceedingly difficult to actually find one
Each Elementalist is capable of shifting into their raw form as needed. The air you breathe could be trying to kill you. It is indescribable, the foreboding feeling one gets when nearing an Elementalist, but you will know it if you come across it — and if you do, run.