Zuko fought against his sister trying to stop her, only for her to pin Ursa to the wall.

When asked if something was wrong, Zuko noted that it was nothing he could not handle and vowed to do anything in his power to keep everyone, specially Kiyi, safe. Zuko commented on how calm everything was, like a perfect pane of glass, and Aang told everyone that it was a spiritual place that needed to be respected. Sometime later, Zuko noticed that Aang, Katara, and Sokka were preparing Appa to take off.

Although he had said capturing the Avatar was a greater concern to him than the safety of his crew or himself, he showed compassion to those close to him, choosing to rescue Iroh when he was capturedZuko was able to show mercy, even to his enemies. Zuko tried to tell his mother that she did not have to, reminding her of the life she had made. Zuko decides to break from the Harmony Restoration Movement. At first, he was unable to land any blows against Azula, and was defeated rather easily.Little was seen of Zuko's firebending after he returned to the Fire Nation; however, he was confident enough in his abilities that he offered to teach Aang. He found himself in the direst situation possible—being hunted by his younger sister, the ruthless and relentless Azula,These traits became dominant after Zuko's fever dreams and hallucinations,After his return to the Fire Nation, Zuko thought he had everything he ever wanted: a position of honor, respect, and his father's love.

Their mother, however, loved both but favored him over his sister;A few months later, Zuko and his family were eating together at the palace dining hall, when Azula soon began to brag about opposing their firebending teacher, Frightened, Zuko ran away while Azula stayed to watch. He was happy when the Avatar finally accepted him as his firebending teacher and group member.At the start of his reign as Fire Lord, Zuko was assertive of having the Fire Nation pay for its crimes and having its colonies disbanded. As a child, Zuko could only create small bursts of flame and was by no means focused or controlled in his bending,Around the time of Aang's discovery at the South Pole, Zuko was still learning the basics from Iroh yet was skilled enough to momentarily knock Aang off his ship, but he was defeated when Aang went into the Avatar State.After the Siege of the North, Zuko's firebending became more advanced and powerful. He continued to hold Azula off, while the princess screamed at him to tell their mother that she was destined to become Fire Lord. Aang reluctantly agrees. Suddenly, he spotted smoke coming to Kiyi's room. The next morning, he immediately remembered what transpired the night before and ran frantically through the halls searching for his mother. Inspired by those words, Zuko, who never truly attempted to connect with his younger sister, Azula, tried to do the same.During the search for his mother, and upon finding out that Ozai may not be his legitimate father, he realized that he might not be the true heir to the throne. Created by Michael Dante DiMartino and Bryan Konietzko, the character is voiced by Dante Basco and is portrayed by Dev Patel in M. Night Shyamalan's 2010 film The Last Airbender.
Determined to find his mother, he turned to the only person who he believed could help him coax the needed information out of Ozai: Azula.Inspired by the professor's words, Zuko returned home and placed his father and sister in adjoining cells in order to facilitate conversation between the two in hopes of gaining information about Ursa's whereabouts.

Upon receiving the simple answer that Sokka did not mind getting the short end of the deal with his sister, Zuko was inspired to treat his own sister better and covered her with a warm blanket as well.
He is also a supporting character in The Legend of Korra. Azula wondered why Zuko continued to fight, knowing he wanted to be free of the burdens of the throne, and also wondered why he did not throw both her and the letter off the cliff the other day.