I was thinking of having my character on the move with a small group of people, no more than 2 or three others not counting himself. If we're going to have a metal bender as the "King" Or the earth kingdom, I think it would be interesting to have My character and his friends running from his men. Eventually, the men catch up to my character and intend to come back his head head and the heads of his friends. His friends die before him and just before it happens to him, the avatar state activates. 

It doesn't have to go exactly like that, but i was thinking that since this seemed a bit darker, I'd make it darker as well.