Aang is the last surviving monk of the Air Nomads gifted with the ability to manipulate or "bend" the element of air. When Aang was 12, it was determined that he is the reincarnation of the Avatar, an individual of great power gifted with the ability to bend all four elements of earth, water, air, and fire. The purpose of the Avatar is to maintain a peaceful balance between the elements. Aang's mentor Monk Gyatso felt that even with this great power, Aang should still be treated as a child. The other monks disagreed and decided to send Aang away to the Eastern Air Temple to separate him from Gyatso. Upset by this news, Aang flees from the Air Nomads on his flying bison Appa where he is caught in a violent sea storm. Caught in this moment of distress, Aang freezes himself and Appa in the water where they remained in suspension for 100 years.
Aang was discovered 100 years later in his iceburg by two water tribe members named Katara and her brother Sokka. Aang realized that the world was in danger of the Fire Nation, or people who could "bend" fire. Aang set out with Appa, his flying bison, Katara, and Sokka to find teachers for earth, water, and fire bending.