Azulon

Fire Lord Azulon is a minor antagonist in Avatar: The Last Airbender and the father of both Iroh and Ozai.

History
Azulon was born to Sozin and his unnamed wife sometime after Sozin's Comet arrived. He was more cruel than his father and led some battles that ended in victory.

After Sozin died, Azulon was crowned Fire Lord. During his years as Fire Lord, he was responisible for the genocidal attacks on the Southern Water Tribe which nearly wiped out all of the waterbenders. He later conducted another raid that killed Katara's mother.

When his first born son Iroh lost his only son in the Siege of Ba Sing Se, Ozai tried to usurp Iroh's birthright, stating that his children are alive. Azulon, outraged ordered Ozai to murder Zuko to see how it feels to lose his son. However, Ursa planned with Ozai to spare Zuko and that would make him Fire Lord. During that night, Ozai with Ursa's help killed Azulon and Ozai was crown Fire Lord the next morning.