The sequel series reveals that Fire Lord Zuko aided Avatar Aang reorganizing the Fire Nation 's colonies in the Earth Kingdom as a United Republic of Nations .
Is the only one of Republic City 's founders not to have lived there .
The sequel series reveals that Fire Lord Zuko aided Avatar Aang reorganizing the Fire Nation 's colonies in the Earth Kingdom as a United Republic of Nations , and is the only one of Republic City 's founders not to have lived there .