Azulon

History
Azulon was the son of Fire Lord Sozin, instigator of the war. He was also the previous Fire Lord before Fire Lord Ozai. He was the husband to Fire Lady Ilah, and the father of Fire Lord Ozai and General Iroh, and thus grandfather to Prince Zuko, Princess Azula, and Prince Lu Ten. Like Iroh, Azulon was apparently a general in the war years before becoming the Fire Lord and once searched for the Avatar as his father and grandson did. His granddaughter Azula is named after him.

Azulon was the Fire Lord of the Fire Nation for almost twenty-three years until he mysteriously died about six years ago. Fire Lord Azulon ran the Fire Nation much like his father did – with an iron fist, and was a frightening man who demanded perfection. Fire Lord Azulon, like every Fire Lord, was a master Firebender. In his time, he was considered one of the best in the world and no one would dare cross him. Despite his strong leadership, Azulon cared very little for the people of his nation and was more interested in world domination, a quality he passed down to Ozai. Some of his greater military successes included the conquest of the Hu Zin provinces in the Western Earth Kingdom and the Battle of Garsai.

Shortly after the death of Iroh's son, Lu Ten, Ozai demands that Iroh be passed over for the throne and incites his father's fury. Ozai declares Iroh is a quitter and unworthy for letting death get in his way of winning Ba Sing Se. He also said that the bloodline would not continue with the death of Lu Ten. However, Azulon was outraged at the very thought of betraying his firstborn Iroh, as well as his younger son's ambition, and promised to punish Ozai terribly. Azula who spied on the conversation claimed that Ozai was ordered to kill his first born son, Zuko, so that he would know his brother's pain. Azulon dies soon afterwards by an unknown cause after a twenty-three year reign. Ozai then inherits the throne, supposedly on Azulon's dying wish, although possible that Ozai killed Azulon and then fraudulently pronounced that Azulon wanted him to become Fire Lord.

However, in season three's first hour-long episode, "The Invasion/The Eclipse", Prince Zuko confronts his father, Fire Lord Ozai, and informs him that he will be joining the avatar and helping him to end the war. Upon hearing this, Ozai, considering Zuko to be a traitor of the Fire Nation, reveals to him that Ursa (Zuko's mother) commited "many treacherous things" the night she disapeared. This implies that she is responsible for Azulon's death resulting in Zuko's protection from the former fire lord's command and Ozai's rise to power as the new fire lord.

Relatives
See Fire Nation Royal Family Tree