Aang (Mitchel Musso in the unaired pilot, Zach Tyler Eisen onwards) is the fun-loving, 12-year-old (chronologically 112-year-old) protagonist of the series. He is the current incarnation of the Avatar, the spirit of the planet manifested in human form. As the Avatar, Aang must master all four elements to bring peace to the world and balance to the four Nations.[26] A reluctant hero, Aang openly admits that he would rather be searching for adventure and making new friends than saving the world. Aang's energetic nature, childish naïvete and innate distractibility render him mildly oblivious to both the world around him and the feelings of others. However, over the course of the series, Aang's experiences gradually mature him as he grows into his role as Avatar. The blue arrow on his head, hands and feet are to show that he has mastered Airbending. Aang is the youngest Airbender to do so.
Katara (Mae Whitman) is a 14-year-old Waterbender of the Southern Water Tribe. As a result of targeted Fire Nation raids, she is the only remaining Waterbender in the South Pole. Katara discovers and frees Aang from an iceberg that he has been trapped infor one hundred years. With her older brother Sokka accompanies him on his quest to defeat the Fire Lord and bring peace to the war-torn nations. Katara is kind, responsible and particularly motherly, a trait she developed after her own mother was killed in a Fire Nation attack. Though an apt leader,[27] she can be overbearing and stubborn.[28] In spite of her kind nature, she also has a temper, which, when combined with her idealism and impressive waterbending skills, can be quite destructive.
Sokka (Jack DeSena) is a 15-year-old warrior of the Southern Water Tribe who, with his sister Katara, accompanies Aang on his quest to defeat the Fire Lord. The joker of the group, Sokka describes himself as "meat-loving" and "sarcastic."[22] Unlike his companions, Sokka cannot bend an element. However, the series frequently grants him opportunities to demonstrate his true gifts: ingenuity and use of weapons. He takes great pride in his mental and physical strength, though it is often overshadowed by others' ability to bend. He is extremely clever, relying on science where the mystical and martial arts elude him (thus, giving him great advantage as strategist), though his immature manner often causes others to underestimate his intellect, and learns what it means to be part of a team.
Toph Bei Fong (Jessie Flower) is a 12-year-old, blind Earthbender who leaves her wealthy family and home to join Aang on his quest in order to teach him earthbending. Though blind, Toph "sees" with Earthbending, feeling vibrations in the ground through the soles of her feet. Using this method, she eventually learns how to bend metal, a knowledge which may be unique to her. Toph has lived a largely sheltered life due to overprotective parents, which makes her somewhat selfish, sarcastic, and, at times, bitter and arrogant. She does not hesitate to speak her mind and is bluntly truthful. With the presence of friends, Toph gradually becomes less abrasive
Zuko (Dante Basco) is the exiled 16-year-old prince of the Fire Nation and original primary antagonist of the series. Zuko was obsessed with capturing the Avatar in his quest to restore his honor and redeem himself in the eyes of his father, Fire Lord Ozai, who deems him a complete failure. The most defining aspect of his appearance is the scar over his left eye, which he received during a forced Agni Kai with Ozai.[29] As a result of his traumatic life, including the disappearance of his beloved mother Ursa, Zuko is temperamental, bitter, and cold to others. However, he is positively influenced by both the presence of his Uncle Iroh and his time in exile. Over time, Zuko struggles to deal with his anger, self-pity, and familial relationships, while growing sympathetic to the peoples his nation has terrorized.
Azula (Grey DeLisle) is the 14 year-old-princess of the Fire Nation, Zuko's younger sister, and one of the major antagonists of the series. Cruel and self-centered since her early youth, Azula is manipulative, sadistic and a self-admitted monster. She has no qualms about bullying and threatening her relatives or her underlings, reserving any familial loyalty for her father, who favors her. As a ruthless firebending prodigy, and one of the few Firebenders shown to generate lightning, Azula is a dangerous opponent. [23]
Iroh (Mako in seasons 1 and 2, Greg Baldwin onwards) is a retired Fire Nation general and Prince Zuko's uncle. Iroh is the older brother of Fire Lord Ozai and was the original heir to the throne of the Fire Nation.[30] A powerful Firebender of great renown and respect (he is known as the Dragon of the West), he looks upon Zuko as a son more than as a nephew, especially after the loss of his own son, Lu Ten. On the surface, Iroh is a cheerful and kind old man whose hobbies include drinking tea, playing Pai Sho, and singing. But underneath the exterior, remains a competent warrior and devoted surrogate parent. Much older, more powerful and more experienced than the other main characters, Iroh chooses to take a less active role in the affairs of the series, acting as more of a mentor and guide to Zuko and nearly everyone he meets