Zuko is one of the best-written characters in all of fiction and arguably the best example of a face turn, as he goes from a despicable antagonist to one of the show’s greatest heroes.
In the episode “The Storm,” which changed everything for the series, we find out the tragic story of Aang and Zuko, and how the latter went from a gentle kid to a hateful prince after being forced to fight his father in a mortal duel and getting his face burned. Throughout the cartoon, we find out more about Zuko’s toxic family, and how his mom, Ursa, heavily favored him over his sister Azula (who grew up to be a monster).
We also discover how Zuko’s father, Prince Ozai, trying to take the throne from his older brother, Iroh, led to Zuko’s grandfather, Fire Lord Azulon, punishing Ozai by making him sacrifice Zuko. Upon learning this, a shocked Ursa made a deal with Ozai to space their children by helping him become Fire Lord — and murdering Azulon. Though they succeeded, Ursa was forced into exile, and the last we see of Ursa is her saying goodbye to Zuko.
In the finale, we see Zuko ask Ozai about what happened to his mother — the only hint audiences got that this plot thread hadn’t been forgotten. Though we didn’t get an answer in the show, at least we got this scene, not thanks to DiMartino.
“I will take full responsibility for adding this scene,” co-creator Bryan Konietzko jokingly said in the audio commentary for the finale. “Not only did I want Zuko to address where is his mother. To me, it’s not so much the information, where she is, it’s the fact that their positions are reversed now, and Zuko has control over his father.”