Rangers are known as the Knights of Nature, because the combine - or at least try to make a compromise between - the martial prowess of a Warrior and the magic of Druids, just like Knights do between Warriors and Clerics, or Battlemages between Warriors and Magicians. However, unlike Druids, the main job of Rangers is to guard the borders, police the wildlands, circulate news and announcements, and so on. In wartime, they also serve as the elite infantry of Dragoc.
Being a Ranger comes with the bonuses of receiving advanced archery and swordsmanship skills, basic stealth and basic tracking.
In the video game adaptations of the FRPG, Rangers are a compromise between Warriors, Thieves and Druids in the sense that they can use most weapons, are relatively fast and offense-oriented, can only wear a limited amount of armour, and can cast spells like Druids, but at a much more limited manner, due to the lesser amount of spellpoints.