Zuko is a Firebender, born as a prince in the Fire Nation royal family. His story often paralleled that of the Avatar, Aang. Initially an antagonist, Zuko's life revolved around trying to capture the long-lost Avatar to end his banishment to regain his honor as Crown Prince of the Fire Nation.
Zuko is easily recognized by the characteristic burn scar on the left side of his face given to him by his harsh father, Fire Lord Ozai shortly before his banishment. On his journey to capture the Avatar, he is assisted by his uncle Iroh to master Firebending, hoping to become as powerful as his prodigious younger sister Princess Azula.
With support from Iroh and after much internal struggle and turmoil, Zuko rejects the Fire Nation and joins the Avatar's group to become Aang's friend and Firebending teacher. After Aang defeats Zuko's father, Zuko takes his place as Fire Lord and declares the end of the war and the start of an era of peace and kindness.