Spirit-Bending

In the time before the avatar, we bent nothing but the energy within ourselves.
- Lion-Turtle, Avatar: The Last Airbender

So, barring any extreme returns, Avatar is over.

That was a pretty good last 2 hours of animation. It leaves so many questions but manages to give us closure on the big points. The world can start to rebuild itself after 100 years of war.

Also, Azula really snapped there. Completely bat-$#!% insane.