Zuko

Zuko was a villain in Avatar The Last Airbender especially in the first season. He was banished by his father, Firelord Ozai and seeked to capture or kill Avatar Aang to redeem himself. He gradually became good and eventually joined Aang's companions. He became Firelord after he defeated his sister Azula on the day that would have marked the coronation of his sister as Firelord.