Aang

The primary protagonist of the series. He is the current incarnation of the Avatar, the spirit of the planet manifested in human form. A reluctant hero, Aang often acts in a fun-loving, carefree manner. His pacifist and vegetarian nature demonstrates his love for life, a primary trait of Buddhism. The creators intended Aang to "defeat enemies with his wits" and be a "trickster hero". Though Aang generally acts in a playful, carefree manner, he becomes more serious during crisis and danger.

Katara

The last remaining water-bender from the Southern Water Tribe, due to an invasion by the Southern Raiders and kidnapping of all water-benders in the tribe years previously. By the age of fifteen, she had mastered the art of water-bending, and thus began teaching Aang Waterbending simultaneously to his studies on earthbending. A "protective sister" for the group; Katara is still very stubborn and described as "a generic anime heroine" by SciFi.com. Katara is shown to be a very skilled Waterbender, one with the ability to cut through objects, to manipulate water whips, and the ability to bloodbend, which allows her to control the water in another's body.

Sokka

A 16-year-old warrior from the Southern Water Tribe and Katara's brother. After rescuing Aang from the iceberg and learning of him being the Avatar, he along with Katara accompanies Aang on his quest to master the four elements and defeat the Fire Lord, ending the war and bringing peace to the world. Although he hails from a tribe of people with the ability to bend water, he was not given the gift and instead strives to become a worthy warrior and leader. Instead of bending, he is frequently given opportunities to use his ingenuity and weapons, including his boomerang, machete, and a space sword he forged from a meteorite.

Toph Bei Fong

A blind Earthbending master of the prestigious Bei Fong family in Gaoling. Her parents are overprotective and view her blindness as a disability. To avoid them, Toph learned Earthbending from Badgermoles and became a famous fighter for a time. She later fled her home to completely escape her family's control on her and to help Aang master Earthbending. Toph is fiercely independent, sarcastic, direct, brutally frank, and confrontational, commonly depicted as the choleric and tomboy of the group. Unlike other Earthbenders, her blindness produced a distinct style of earthbending that is not based on Hung Gar as is conventional, but rather the Southern Praying Mantis.

Prince Zuko

Prince Zuko was originally the primary antagonist of the series, but developed into an anti-hero and tragic hero and later, a protagonist. Zuko had been exiled prior to the beginning of the series by his father, and believed that capturing the Avatar was the only way to regain his honor. Zuko's ancestry reflects his own conflicted nature; his paternal great-grandfather is Fire Lord Sozin, the one who started the war, while his maternal great-grandfather is Avatar Roku.

Appa

Aang's sky bison who serves as the group's main form of transportation around the world. He was stuck in suspended animation with Aang for 100 years, and shares a very strong bond with him. He possesses the ability to fly and can use his tail to create powerful gusts of air. Aang said that the flying bison were the first Airbenders.