Water Tribe
The Water Tribe is divided into two nation-states: the Southern Water Tribe, which inhabits the South Pole, and the Northern Water Tribe, which inhabits the North Pole. There is also a small population of Waterbenders located in the swamps of the Earth Kingdom. The Water Tribe is home to an order of men and women who practice waterbending, the mystical art of hydrokinesis. According to Uncle Iroh, Waterbenders can adapt to different situations easily, as they manipulate water, the "element of change."
Earth Kingdom
The Earth Kingdom is a massive continent taking up most of the planet's eastern hemisphere, roughly geographically analogous to Eurasia in our world. The Earth Kingdom is home to an order of men and women who practice earthbending, the mystical art of terrakinesis.
The Earth Kingdom has long withstood encroachments on their borders in the Fire Nation's century-long imperialist war. Though the Water Tribes aid the Earth Kingdom in the war, the conflict continues to progress poorly. Other than the Avatar the Earth Kingdom was the only real obstacle between the Fire Nation and complete world domination, as the Water Tribes have thus far demonstrated that they can only defend their own lands, the poles. However, by the end of "The Crossroads of Destiny," the Fire Nation princess, Azula, was firmly in control of the Earth Kingdom capital city, Ba Sing Se. By the following summer, it is firmly occupied by Fire Nation forces.
Fire Nation
The Fire Nation is located near the planet's equator in the western hemisphere and comprises an archipelago of volcanic islands. Regardless of its ancestral boundaries, the Fire Nation militia is engaged in numerous campaigns around the globe and much territory has been lost to the Nation's colonization over the course of the century-long imperialistic war. The Fire Nation is home to an order of men and women who practice firebending, the pyrokinetic ability to create and control fire.
Air Nomads
The Air Nomads were wanderers by definition, but had four Air Temples, one at each corner of the globe, hidden away atop mountain ranges in the northern Earth Kingdom and on three remote islands. The Air Nomads were home to a monastic order of men and women who practiced Airbending, the mystical art of aerokinesis.
A century before the time of the series, the Air Nomads were the victims of genocide at the hands of the Fire Nation. The sole known survivor of the massacre ironically was the very person the Fire Nation sought to kill in its quest for supremacy: the twelve-year-old Airbender and Avatar, Aang, who had run away from the Southern Air Temple shortly before the war began and became trapped in suspended animation. He has since revived and begun a quest to restore balance and peace to the warring nations.
