What nation is Aang the last surviving member of?

Aang is the last surviving member of the Air Nomads. He is an Air Nomad monk from the Southern Air Temple and the Avatar, the one person able to master all four elements.

The Fire Nation’s war began with the genocide of the Air Nomads, carried out during a comet-enhanced attack ordered by Fire Lord Sozin. Aang survived only because he fled on his flying bison, Appa, and became trapped in an iceberg for a century.

When Katara and Sokka discover him, the world believes the Air Nomads have been wiped out. Aang later preserves their traditions by founding the Air Acolytes, a group of non-Air Nomad followers dedicated to Air Nomad teachings. The phrase “last surviving member” refers to the original Air Nomads, not to every later person connected with their culture.