One of the main pieces of lore in the Avatar: The Last Airbender universe is that the Avatar is constantly reincarnated into a new form. This means that there have been a slew of different Avatars from over the years, all with their own unique stories and life paths. Some of these Avatars are more well-known than others, as the series puts more focus on them, like Aang, Katara, Kyoshi, or Roku, for example.