Prior to the events in Avatar: The Last Airbender, the Avatar World entered a war started by Fire Lord Sozin. Although he was threatened by Avatar Roku, Sozin carried on with his plans after leaving Roku to die in his home. In an attempt to destroy the Avatar Cycle, Sozin eliminated all the Air Nomads with the help of Sozin's Comet. Following that, he continued his attacks on the Earth Kingdom, particularly Ba Sing Se, and sent the Southern Raiders to weaken the Southern Water Tribe. Fire Lord Sozin then spent the rest of his life searching for the new Avatar.