Avatar Aang saves the world but ruins himself in the process. or Katara engages "He who saved the world" but loses herself in the process. - Aged up. when the battle against Ozai takes place Aang is 18, Katara is 20, Zuko is 22.
When Aang was shot down and claimed to be dead... Another had fallen and was also claimed dead, accept he was really dead. Prince zuko. When the gaang finds out the tragic death of the prince of the fire nations murder they almost seem to feel it's unreal, the boy that have hunted them will never bother them again...