ZukoxKatara. Also referred to as: "Zutara". It is the relationship between Fire Prince Zuko and Waterbending Master Katara. It has been hinted to, but isn't officially a "couple" yet...
ZukoxKatara or Zutara is thought of usually as Pride & Prejudice. Although it seems as though they have no romantic encounters, they have indeed had moments in which enough is progressed. "The Crossroads of Destiny" is said to have took their relationship further when Katara offered to heal his scar. He let her touch his scar, which he hadn't let anyone else done before. This is mainly a 'fanon' ship, which means that it is mostly shipped because of the genuine like of the two seen together. However, it is shipped by more than half of the fanbase. And although Kataang (the ship of AangxKatara) seems to be canon, Zutara becomes more popular with each passing day. Howver, Season 3 of Avatar: The Last Airbender has yet to air. It is currently debated that either Kataang or Zutara will become 'canon'. Zuko's betrayal of the "Gaang" as they are called, put a damper on the relationship of Zuko and Katara. Aang went into the Avatar State, and supposedly lost his feelings for Katara. However, it has been confirmed that he did not lose them. The water Katara was going to use on Zuko to heal his scar had to be used on Aang when Azula killed him whilst in the Avatar State. Katara and Zuko battled furiously in the end, much to the dismay of the fanbase. No one knows for sure what will become of the Zutara relationship for Season 3.