Just as Clerics and Paladins draw from the Arch Seraphs and Arch Daemons for their powers, so to do Druids and Rangers draw their magic from ancient transcendent beings. These beings of pure nature, also known as Primordials, have their own elemental planes of existence that they reside in, and allow mortals to draw magic from these domains should they follow their teachings.
There are three important centers in Etharis for learning nature magic: the druid circles of the Valikan Clans, the Order of the Golden Bough in Eastern Nordenland, and the elves of Tol Leyemil. These are not the only places for learning, but druids and rangers that emerge from here are considered to be elite.
As a druid or ranger, you must keep in mind that your power is derived from the Primordials - including Gormadraug. These beings have taken over the realm of gods in terms of nature magic. They each serve their own interests and are not bound by mortal notions of good and evil. They are, however, hostile to all that threatens that power. This includes the possible awakening of Gormadraug, the corruption of nature caused by the Dark Mist, and the arrival of the Great Beast. The Primordials require druids and rangers alike to fight these forces wherever they encounter them.