From the intro:
"The wizard is an archetype of power. With courage and discipline he ventures into forbidden mysteries, learning the spells which may melt down reality and remould it closer to his heart’s desire. Once the heady heights of ninth level spellcasting are attained, the magician is believed to be at the apex of his power. However, there are those for whom this is just the beginning.
These are the sovereign mages, those who have learned the rare art of entering the soul of the land and binding their personal power to it. Not content with merely moving upon the face of the earth, they seek to become one with it; some to conquer, some to protect. By infusing their very essence into the country around them, they partake of the energies of the land, drawing upon it to achieve legendary and miraculous results. The wild beasts of the region seem to know and obey them. Some even send forth weird allies and emissaries, whose eyes and ears the sovereign mages may use and through whom they may speak. Some, the darker ones, are even said to take possession of important figures against their will. Whether they serve as governors, custodians or power-mad conquerors, they are a more potent magical force than any ordinary spellcaster could hope to be. The more land they take over, the more their ability to influence it grows. Their arcane spellcasting abilities are augmented massively and they become able to cast spells over huge distances, raining down their magic upon the unwary who had thought themselves safe in far-off lands."