Korra
I wasn't able to stop Brainiac when he came to my world. My friends and I fought as hard as we could against his legions of machines, but we were unable to stop him from stealing Republic City, trapping everyone I ever cared about within it the process. As if to insult to injury, that bastard destroyed my world after taking what he wanted. That would've been the end of me too had in not been for a portal opening up at the last second and sending me to another dimension that was ruled by beings called the Lords of Order. They told me that my world's destruction created an imbalance between order and chaos, and they wanted me to fix this little problem.
So, they sent me to another world where Brainiac was going to do the same thing he did my world, and this time I was ready for him. I've fought bending-stealing pyschos, directors, anarchists and my own uncle, but nothing felt more satisfying than pummeling the little green freak who blew up my world and stole the last shred of everything I held dear to a bloody pulp. While I managed to recover Republic City out of Brainiac's collection, there was still the problem of bringing it back to regular size, not to mention that our world was gone.
Thankfully, the world that the Lords of Order had sent me to had its fair share of geniuses, and with their help, we managed to figure out how to restore Republic City and the people within to their normal size. However, Batman suggested that we find somewhere else to bring back my city considering that it would be too much of a culture shock for everyone to restart their lives here. As luck would have it, A man named Adam Strange and the people of his adoptive planet of Rann where more than happy to let us stay with them as a way of saying thank you for me stopping Brainiac.
Now where here, citizens of Rann and sharing our two cultures. I may no longer be connected to my past lives, but I'm sure Aang and the other past Avatars would agree that I did the best I could in this situation. I lost my family when Brainiac destroyed my world, as did hundreds of others in Republic City, but at least I still have Asami and my friends with me. It's not going to be easy for any of us to adjust to our new home, but as the Avatar, I'll do what I always do: keep the balance.