Zuko (Voiced by Dante Basco) is the exiled prince of the Fire Nation and original antagonist
Zuko was the first-born (83 ASC) of Fire Lord Ozai and Princess Ursa. From an early age, he was disdained by his father and the object of his sister Azula's manipulation, ridicule and deception. His mother, however, loved and favored him over her. At some point in his childhood, Piandao trained him in the Dual Dao Swords.
When Zuko was about eleven years old, his cousin, Lu Ten, died while away at war. General Iroh, devastated by the loss of his only child, abandoned his almost two-year siege of the Earth Kingdom capital city, Ba Sing Se. During an audience with Fire Lord Azulon, Ozai showed off Azula's prodigious Firebending skill and knowledge of military strategy, both outstripping Zuko's. Azulon was unimpressed by these exercises and demanded Ursa and her children leave and Ozai be frank about his reasons for wanting the audience. Azula and Zuko eavesdropped on their conversation as Ozai voiced his desire to be made heir in Iroh's place, justifying this course of action by pointing out that Iroh’s overwhelming grief and subsequent erratic behavior made the date of his return from war uncertain and he had no remaining heirs to carry on his line. Azulon, however, was outraged and declared angrily that Iroh had suffered enough, but Ozai’s suffering had just begun.
Ursa embraces Zuko before her mysterious disappearance.Added by Renatabls Frightened, Zuko ran away; Azula stayed to watch. Later, he was in his room trying to sleep when she came in and mockingly told him that Azulon's punishment for Ozai is that he must kill Zuko, as he wanted him to know what it felt like to lose a child. Ursa, hearing the commotion, came in and took Azula away, declaring it was time that they talked. Zuko, left behind, chanted quietly to himself, "Azula always lies." Later, he was awakened again, but this time by his mother. She told her sleepy son everything that she had done, she did for him, and instructed him not to forget who he was no matter how much things may change. The next morning, he immediately remembered what transpired the night before and ran frantically through the halls searching for his mother. He found Azula, who blithely told him Azulon died the previous night and their mother was missing. As she played with his pearl dagger (a gift from his Uncle Iroh), she mocked him and noted their mother was not there to make her give it back. Eventually, he found Ozai in the gardens of the palace and demanded to know where Ursa was. Ozai did not answer and he hung his head in sorrow. At Azulon’s funeral, the sage conducting the ceremony named Ozai the new Fire Lord upon Azulon's dying request.
Zuko pleads to his father for forgiveness.Added by Thailog Years later, Iroh allowed a persistent, thirteen-year-old Zuko into a war council with Ozai and some of his generals. He ignored Iroh's instructions not to speak during the meeting when one general outlined a plan to sacrifice an entire division of new recruits in a diversionary maneuver. He fiercely disagreed with this, seeing it as a betrayal of the recruits' patriotism. The insubordinate outburst was seen as a grave insult and Ozai demanded that he participate in an Agni Kai. He agreed, unaware he would face his father, not the general he insulted. Upon turning to face his opponent, he was immediately penitent and knelt, refusing to fight, and tearfully begged for his father's forgiveness. Ozai declared his refusal a sign of cowardice and another display of disrespect, and told him "[he] will learn respect, and suffering will be [his] teacher."
Ozai burned Zuko (permanently scarring the left side of his face), stripped him of his birthright, and exiled him from his beloved homeland, declaring that he could only return if he was able to find and capture the Avatar, who disappeared one hundred years before. A fool's errand by all accounts (because if the Avatar had disappeared, there would be no point in searching for him), but one Zuko clung onto desperately as his only hope of regaining his honor, and everything he had lost.
Zuko spent the next three years at sea, fruitlessly searching for the Avatar. He searched the four Air Temples, beginning with the Western Air Temple, and scoured the world, searching even the most remote locations for his prize. Iroh accompanied Zuko during his exile, and the pair spent more than two years at sea with a small ship and crew. They were not royal guards or special forces, and may well have been banished themselves, or were foolishly intent on serving under the popular General Iroh. They were often unhappy under Zuko but obeyed his orders. Iroh often considered the search an extended vacation.
After the War Edit
After the War, Zuko became the Fire Lord. He and Aang founded the United Republic territories and its capital of Republic City, which quickly grew into a metropolis. It is presumed he has died along with the other main characters by the time The Last Airbender: Legend of Korra takes place.
Initially the series' main antagonist, Zuko is a bitter and complex young man, akin to a tragic villain. He wanted, more than anything, his place as heir to the Fire Nation throne and his father's love. Zuko believed, or forced himself to believe, that capturing the Avatar would make these wishes come true, making him one of Aang's most determined enemies. His motivation stood in contrast with other pursuers; Zhao and Azula were motivated by political ambition or cruelty.
As an adolescent, Zuko demonstrated empathy for others despite his pompous attitude.Added by Thailog Zuko believed one becomes strong by struggling and fighting for what they want. He expressed contradicting beliefs: he did not want good luck because he felt he could control his fate, but also believed he is marked unlucky and the world is against him. His reaction to the perception of the world always set against him is an iron-willed defiance and inflexible determination. He was clever, yet hot-headed, often letting his temper get the best of him. He seemed adverse to the thought of harming others when there is no motive or nothing to gain, having consented to Aang's request to spare the Southern Water Tribe in exchange for himself as his prisoner, and left the village unharmed. He rarely thinks his situations through, causing him to get in trouble; when he captured Aang at the North Pole, he could only walk into a blizzard afterward, or when he took the Sunstone off its pedestal in the Sun Warriors' temple and fell into a trap. Said traits are criticized by his uncle, and he tries to control himself and think things through more often towards the end of season three.
Zuko has other contradictory traits, beliefs, and behaviors. He is domineering and controlling, a result of his upbringing as Fire Nation royalty, and disdains working with people he believes are inferior; yet, he adamantly refuses to view people as expendable. He believes it is wrong to sacrifice able-bodied and willing troops as a diversionary tactic. During his banishment, he displayed zeal in pursuing the Avatar, using whatever means he thought necessary. Although he has said capturing the Avatar is 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 captured, rather than pursue Aang, and risked his own life to save a member of his crew during a fierce storm. When the crew spotted Aang, he ordered the ship and crew to safety instead of chasing the Avatar.
Zuko has experienced substantial turmoil due to the events of his life.Added by Thailog The prospect of returning home and forgiveness was Zuko's sole motivation. After losing his first chance at the Northern Water Tribe, he was filled with abject despair. He found himself in the most dire situation possible—being hunted by his younger sister, the ruthless and relentless Azula, while attempting to survive as a penniless fugitive in the Earth Kingdom. Apart from his ever-supportive uncle, Zuko had nothing. At first, he lashed out and turned to robbery, even stealing from those who were kind to him. After some time, however, partially in thanks to a talk from Iroh, he gained a more reasonable outlook. Theft was still necessary from time to time; he refused to steal from needy people or people showed him kindness. He defended a Earth Kingdom village against a group of thugs who terrorized its people. He became more patient, kind, precise and calculating; said traits necessary to evade Azula's pursuit while staying incognito from local authorities. He set Aang's pet bison and primary mode of transportation, Appa, free from Dai Li captivity at Iroh's suggestion.
These traits became dominant after Zuko's fever dreams and hallucinations, as afterward he displayed an optimistic attitude towards life and the world. However, Azula successfully manipulated his desire for love and approval from his father, convincing him to betray Iroh and become her ally. He continued to insist that he had truly changed, but felt conflicted about his choices afterward, uncomfortable with his betrayal of Iroh, a father figure to him.
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. However, he still felt angry and confused. He felt his triumph was nothing like he imagined. His temper goes out of control; he becomes suspicious of Mai and gets into fights with several people. Later, he states he was angry with himself, saying he doesn't know right from wrong. He receives a letter telling him his great-grandfather's death would reveal his destiny. He found Sozin's last testament and learned of his history with Avatar Roku. Assuming the letter was sent by his uncle, he visited him in prison, demanding to know the message's meaning. Iroh explained Avatar Roku was his mother's grandfather, and Zuko's inner conflict was part of the legacy of his forefathers' conflict. Iroh presented him with the Crown Prince Headpiece, an ancient royal artifact, traditionally worn by the crown prince of the Fire Nation, and given to Roku by Sozin in their youth.
Zuko became upset when he wasn't informed of a war meeting his sister was invited to, and showed happiness when a servant later came and asked him to head to the war room, as Ozai would not start the meeting without him. He told Mai he found himself unhappy, even when his father treated him as the perfect son. He said during the meeting, he had acted the perfect prince, the son his father had always wanted, but he was not being himself.
During the events of Day of Black Sun, Zuko realized it was his duty as the heir to the Fire Nation throne to restore peace to the world by joining the Avatar and fighting the his father's (and forefathers') tyrannic regime. His zeal and resolve resurface in an entirely different direction. He resolves to confront his father and his many evils. He reveals in a discourse his banishment made him a firsthand witness to the misery and pain the Fire Nation has inflicted on the World. He discovered sharing the Fire Nation's greatness had nothing to do with the war - only fired by a ruthless desire for power. He swore to his father he will do everything in his power to see his defeat. He attempted to free Iroh from prison, but when he escaped by himself, Zuko followed Aang and the others as they fled to the Western Air Temple.
Zuko is finally at peace upon joining Team Avatar.Added by Thailog While at the Western Air Temple, Zuko showed a complete change in personality. After a flashback of his banishment, he was regretful about his former disrespect and ruthlessness. For the first time he showed a comical side to his personality while practicing a speech to a badgerfrog. After questioning what Iroh and Azula would do, he tried impersonating them. He later admitted his wrongdoings to Team Avatar and apologized for the things he did. Out of resentment, his request to join them was initially rejected; he humbled himself and offered himself up as a prisoner-- a stark contrast to the proud young man shown at the beginning of the series.
Rather than trying to capture the Avatar for the Fire Nation's benefit, Zuko joined him to end their tyranny. He used to attack Aang whenever they met; instead he defended him from the assassin he hired to kill the Avatar. He realized his father could never restore his honor, and he had to restore it himself. He was happy when the Avatar finally accepted him as his Firebending teacher and group member. Though he still had some issues to work through, he was far more composed and receptive. Since coming to terms with his own true feelings he is more laid-back and empathetic. After joining the group he smiled a lot more than usual, even when jokes were made at his expense, and he seemed very happy as Fire Lord during a break in his uncle's tea shop.
Zuko demonstrating his new foundation of Firebending.Added by Thailog Throughout the series, Zuko has shown himself to be a highly skilled Firebender and his prowess considerably increased throughout the course of the series, to the point of becoming a Firebending master.
As a child, he could only create small bursts of flame, but by the time he was thirteen, he was confident enough in his abilities to readily accept a challenge of Agni Kai (he refused to fight, however, when he found out his challenger was his father).
Book 1 Edit
At the beginning, he was still learning the basics from Iroh and was skilled enough to momentarily knock Aang off his ship, but he was defeated when Aang went into the Avatar State. He utilized what he had been taught to defeat Zhao, an older and more experienced master Firebender. Throughout Book One, he demonstrated his skill often; he defeated multiple foes on two occasions. Later, his skill grew. He fared well in a duel against Aang, delivering multiple fire blasts for a sustained period without tiring, but was defeated when he was paralyzed by June's confused Shirshu. He created a shield of fire to protect himself from a massive explosion on his ship. During the Siege of the North, he fought Katara while the moon was nearly full. He held his own against her while she was strengthened by the moon, but needed the power of the sun to gain the upper hand and defeat her with one fire-blast. He also landed a decisive victory in a rematch against Zhao.
Book 2 Edit
During the course of Book 2, Zuko's Firebending became more advanced and powerful. At first, he was unable to land any blows against Azula, and was defeated rather easily. He fought somewhat better during the Duel at Tu Zin; in a three-way battle with Azula and Aang, he traded several fire blasts with his sister and kept the Avatar on the defensive. As Book Two progressed, however, he learned more advanced Firebending techniques from Iroh, such as Lightning Redirection, becoming more efficient and refined.  During a battle with the Rough Rhinos, he sent a small bolt of fire through Vachir's bow, breaking the string. He demonstrated the ability to fire multiple small blasts through two fingers, rather than his whole fist. During the battle in the Crystal Catacombs, he demonstrated how far his prowess had grown. His fire blasts were more powerful, and he charged his attacks before releasing them, creating enormous blasts of fire. He also demonstrated the ability to create two fire-whips. He battled evenly with Aang, even though he had skillfully used Airbending and Earthbending. After switching opponents with Azula, he battled evenly with Katara, a Waterbending Master who had the upper-hand against Azula.
Book 3 Edit
Zuko augmenting fire.Added by Thailog Little was seen of Zuko's Firebending in the first half of Book 3; however, he was so confident enough in his abilities that he offered to teach Aang. He utilized a wall of flame to stop an attack from Combustion Man, and was capable of dodging many of Toph's rocks which she hurled at him, though her Earthbending was impeded due to Zuko accidentally burning her feet. Later, he temporarily lost his Firebending from a corresponding lack of rage, the former source of his power. He and Aang then traveled together to the Ancient City of the Sun Warriors to reconnect with the original source of Firebending. There, Zuko learned "The Dancing Dragon", an ancient Firebending form that he performed alongside Aang. Learning this form appeared to have influenced his style of Firebending to be more fluid, creating a more dancelike form as opposed to the rigid, militaristic forms commonly used by Fire Nation soldiers. He was also challenged by the Tribesmen to carry a piece of the Eternal Flame all the way up to the cave of the masters. Zuko and Aang performed their newly learned technique in unison with the dragons, who engulfed them in a spiral of multi-colored flames. After viewing this, Zuko found a new source of power in reverence for fire's power as a source of life and energy: "the sun inside you". His stylistic differences and skill are demonstrated at the Boiling Rock where he briefly battled against Azula alongside Sokka. During the fight, he deflected many of Azula's fire blasts with only his arms or his own fire, and traded fire balls with her.  He later faced Azula again and dueled her evenly for several minutes. He fired several large and powerful fire blasts, deflecting many of her attacks. Later, he attacked Aang with powerful fire blasts to make him fight back. When he chased him into Ozai's old family vacation home, Zuko created several lashes of fire to envelop his surroundings and augmented them to the shape of the hallway Aang was running through. With the power of Sozin's Comet, Zuko's Firebending was tremendously enhanced. He fought Azula one final time in an Agni Kai, unleashing extremely powerful sheets of flame. This time he held the upper hand, exchanging and blocking attacks with her without visible strain while she was pushed towards exhaustion and increasing mental instability. He displayed several incredibly powerful techniques: blocking an enormous stream of fire with a short fire-blast, spreading to take the shape of a wall and split the stream, unleashing an enormous charged-blast, which Azula was unable to block, forcing her to dodge, propelling himself into the air, charging his fire and sending down a fire attack as he came. His final attack was a fire tornado he created with his feet while spinning, knocking Azula off her feet. 
Zuko displays the extent of his bending skills with the arrival of Sozin's Comet.Added by Thailog Furthermore, he used his Firebending in conjunction with his broadswords, demonstrated use of Fire Daggers,and limited use of Breath of Fire .
During his training with Iroh he attempted to learn how to create lightning. His inner turmoil, however, rendered him unable to achieve the required peace of mind, and his attempts to produce lightning would only explode in his face. Instead, Iroh taught him how to absorb and redirect lightning. He later employed this technique against his father  and Azula to protect Katara. In the latter engagement Zuko redirected the blast in an improper stance, as he had jumped into the lightning's path, but failed to redirect all of the lightning he was forced to hold in midair. Though he seems to have overcome his inner turmoil, he does not create lightning for the remainder of the series.
Other Skills Edit
Though a Firebending Master, Zuko is also gifted in the art of Dual Swordmanship.Added by Thailog In addition to his Firebending, Zuko was a master of his dual Dao blades, a skill he picked up after being trained by the Sword master Piandao. He would use his Dual Dao Swords whenever he was in his Blue Spirit disguise, unable to Firebend, or when he needed to fight but also needed to conceal his Firebending. He was able to defeat multiple foes using only his swords. He also dueled evenly with Jet and his dual Hook Swords until the fight was broken up by the Dai Li and Jet was arrested. Zuko defeated several Earth Kingdom soldiers with his Dao swords and minimum effort, only resorting to Firebending when faced with a powerful Earthbender; even then he was able to hold off the Earthbender's attacks for several moments with only his blades. His skill was such that his father, Fire Lord Ozai, opted not to face against him during an eclipse, while neither of them could Firebend.
Zuko was physically very strong, fast and agile. He was capable of great physical feats, such as running across walls, climbing very quickly, and jumping large distances. He is apparently skilled in unarmed combat, able to break apart oncoming spears with his hands and legs, and disarm, subdue or defeat opponents. Zuko is skilled at infiltration, and can sneak into heavily-defended fortresses. He is also skilled at stealth, and can conceal himself effectively for long periods of time. All of these skills would serve him while he was disguised as the Blue Spirit. Zuko was also a skilled tracker, able to track the airborne Avatar all across the world. Zuko was also a gifted Tsungi Horn player, although it is apparently not his favorite instrument.
Disguised as the "Blue Spirit," Zuko made apparent the scope of his abilities without having to rely solely on his bending.Added by Renatabls While not as naturally adept at strategy and academics as his sister, Zuko was quite intelligent. Throughout the series, he had demonstrated himself to be a skilled strategist, able to exploit any situation to his advantage. Zuko used his ship's damages as a smokescreen to conceal his movements from Zhao. He was also able to form alliances with people with special skills, such as June, and use them to his advantage. However, he had a hot-headed nature that caused him to not always think his actions through. For example, he could exploit advantages in the Northern Water Tribe, and get into the Spirit Oasis to capture Aang, but he didn't figure a way back out which caused him to almost freeze to death. Zuko began to think things out more towards the end of the series, and he started to plan things out and think ahead to solve problems more often. When he and Aang needed to get in a specific room in the Sun Warrior ruins, Zuko was able to outsmart the Celestial Calendar, as it would only allow the room to open during a solstice. This intelligence may come to serve him as he rules the Fire Nation.
While never implicitly shown other than briefly at the end of the series, it is heavily implied that Zuko was both a popular and good Fire Lord. As a Prince, he was shown to be quite popular with women swooning over him. His speech to redeem the name of the Fire Nation at his coronation was warmly embraced by the people.