Iroh was a retired Fire Nation general, a former Crown Prince of the nation, a Grand Lotus of the Order of the White Lotus, a firebending master, and a wise mentor to his nephew Zuko. He was the elder son of Fire Lord Azulon and Ilah and the older brother of Ozai.

Azula was the princess of the Fire Nation, daughter of Fire Lord Ozai and Ursa, younger sister of Zuko, and older half-sister of Kiyi. She was a key adversary of Team Avatar, chasing Avatar Aang and her banished brother far across the Earth Kingdom accompanied by her two best friends at the time, Mai and Ty Lee.

Ty Lee was a cheerful and energetic girl who hailed from the Fire Nation. As the daughter of a nobleman, she attended the Royal Fire Academy for Girls with her friends, Princess Azula and Mai. Growing up, Ty Lee dealt with six sisters who shared identical appearances with her.

Mai is an recurring character and the former antagonist turned into the redeemed supporting major character in Avatar: The Last Airbender. She is a non-bender, however she developed her knife throwing skills. She is a daughter of a rich Fire Nation politician and an old friend of Ty Lee, Azula and Zuko. She joined Azula's squad for the reason she hates boredom.

Ozai was a firebending master and, prior to the end of the war, was believed to be the most powerful firebender in the world. After Iroh's only son, Lu Ten, died, Ozai usurped his brother's birthright to the throne in a scheme that resulted in his father's death and Ursa's banishment.

Sozin was the ruler of the Fire Nation from 58 BG until his death in 20 AG, and the instigator of the Hundred Year War. Succeeded as Fire Lord by his son Azulon, he was grandfather to Iroh and Ozai and great-grandfather to Lu Ten, Zuko, and Azula. As a young prince, Sozin was best friends with Avatar Roku.

Ursa was the wife of Ozai and later Noren, mother of Zuko, Azula, and Kiyi, daughter of Jinzuk and Rina, and maternal granddaughter of Avatar Roku and Ta Min.