Everyone has an inescapable regret. This is Katara's.
Katara never went home after the war was over. There were a lot of reasons why, ranging from the fact that once a girl has killed a man by forcing all the water out of his body, it's a little hard just being a stay-at-home mom, to the unfortunate realization that Katara didn't really like the cold, but mostly it was because of Jet.
Katara was never really sure why Jet. It wasn't like she'd known him all that well – she'd been fourteen, for Avatar's sake, and they'd met three days out of twice as many months – but still…Jet. Freedom fighter, betrayer, and all-around bastard. The one man she couldn't save.
Maybe that was why. Katara didn't expend too much thought on it. It just was. Jet…was someone she couldn't save, and Katara was someone who could never go home. Somehow, those two facts were connected.
So she wandered. She wandered all over the Earth Kingdom, crisscrossing the land like the rivers, and everywhere she stayed, she taught a lesson to the people. How to irrigate the fields more efficiently, how to improve public health by putting in sewers, how to dye clothes blue. How to save someone's life.
Katara never said she didn't learn from her past mistakes.
She never stayed in one place, though, not even when Haru proposed, and she never returned to a place she'd already been. And she never visited Ba Sing Se. She couldn't. That city was poison, no matter how much Toph said she'd changed it.
Huh. Toph. Honest, down-to-earth Toph. Strange to think she was the Earth Queen now. Toph had been too much like the earth – too solid and heavy – to ever like politics or lies or any of that stuff. Toph had been the model Earth Kingdom citizen.
Jet had been the real Earth Kingdom citizen. He'd been cruel and ignorant and angry, and he had lied to her. Even at the end, he had lied to her, and she couldn't forgive him for that. She couldn't forgive him for protecting her. She didn't need to be protected. She needed the truth. Hadn't he learned that after the dam fiasco?
Mostly, though, she couldn't forgive him for that last smile. He had no right to look so happy when his life was bruising and bleeding into itself in the cold stone caverns. No right at all.
Finally, years after she had covered every inch of the Earth Kingdom, she staked out a place in some nothing village on the poor edge of nowhere. The people here were kind, such as they could be, but it was a hard life in the forests, where the Fire Nation had swept in like lightning and destroyed anything worth having. The only crops that grew here were children – an extraordinary number of them, all of them angry and wailing against something they can't change.
It was because of them she stayed, because she couldn't walk away from so many potential students. She couldn't walk away, not again.
So she stayed. Made a life, and a school, and a clinic, and a town. People came from miles away, because she was Katara of the Southern Water Tribe, Companion of the Avatar. They stayed for the same reason, but Katara didn't mind. Unlike Aang, she'd never had any problems with making her legend work for her.
"Why did you stay here, of all places? I know your background – why didn't you stay with your brother or the Avatar or the Earth Queen?"
"…well…mostly it was because a long time ago, I failed someone I could have loved, and I see a little of him in the people of this place."
"What do you see in us?"
"Oh, I don't know…innocence, maybe."
"He was innocent?"
"No. But I was, and he should have been."