水
Introduction
Long ago, in a time of peace, the Avatar kept the balance between the four nations of the world — the Water Tribes, the Earth Kingdom, the Fire Nation, and the Air Nomads. In these nations, there are people who have mastered the ability to control their culture's native element, an art form known as bending. They call themselves waterbenders, earthbenders, firebenders, and airbenders — only the Avatar can manipulate all four elements. When an Avatar dies, his or her spirit is reborn into a bender of the next nation in the cycle of water, earth, fire, and air. This cycle provides a natural balance, keeping any one nation from growing more powerful than the others.
As you know, the four nations lived in peace for many generations. But that all changed one hundred years ago when the Fire Nation attacked.
The leader of the Fire Nation at that time, the powerful firebender known as Fire Lord Sozin, had secret ambitions to take over the world by conquering the other nations. When Avatar Roku died, knowing that the next Avatar would be a child who needed training and maturity before he or she grew powerful enough to oppose him, Fire Lord Sozin secretly began to build a fleet of massive ships and train an army of firebenders and soldiers. Throughout the years that the Fire Nation's armada grew strong while the other nations remained ignorant. Then, using the energy of a passing comet, Fire Lord Sozin attacked the water, air, and earth nations at the same time.
Only the Avatar had the skills to stop the ruthless Fire Nation, but when the world needed him the most, the Avatar did not appear. Following the natural cycle — since Avatar Roku was from the Fire Nation — the next Avatar would come from the Air Nation. Sozin's army wiped out all of the Air Nomads, so the Avatar could never return.
Or so the world believed.
The war has raged on for one hundred years. The Air Nomads were believed to have all been wiped out. Most of the great cities of the Southern Water Tribe were destroyed. Many of the Earth Kingdom's cities were taken over by the Fire Nation soldiers, and hope was beginning to fade from the world . . .
Until the day the Avatar returned.