One of the best characters in the entire The Legend of Korra. She was instrumental in the defeat of the Fire Nation, and helped to end the Hundred Year War.
Throughout her time on the show, Katara did many wonderful things. However, there are certainly some that soared above the rest, even going as far as to change the course of the world.
Freed The Avatar
While it might have been somewhat by accident that Katara and Sokka found and freed Aang from the iceberg in the beginning of the show, Katara showed no hesitation in wanting to open it and help Aang once they realized what they were dealing with. While this does show how kind that she is, it also was the catalyst to the Hundred Year War's eventual end.
Agreed To Train Aang In The First Place
It cannot be emphasized enough how important it was that Katara agreed to help train Aang as a waterbender. As the only waterbender in the Southern Water Tribe, the job fell on her shoulders. Despite being so inexperienced herself, she took on her duty with enthusiasm, and was a huge part in Aang being able to master waterbending as quickly as he did.
Stole The Waterbending Scroll
Early on in the series, the crew found a waterbending scroll that would be a huge boon to their training. Unfortunately, the pirates that had the scroll weren't going to part with it easily. Katara ended up stealing the scroll. The situation eventually melted into a huge brawl between... everyone. While the situation put Team Avatar in danger, Katara and Aang both benefitted from using the scroll.
Forgave Aang For Lying To Sokka And Her
When Bato found Team Avatar, there was a chance that Sokka and Katara would have left Aang to be with their father. As such, when a messenger gave Aang the rendezvous map for the group, he hid it.
He eventually itted to this, and though Sokka and Katara were both furious at him, they realized that their mission was more important than wanting to see their dad. As such, they forgave Aang and moved past it, which was incredibly mature for their ages.
Forgave Zuko For Everything
Despite everything that Zuko put Team Avatar through and the indirect harm that he inflicted on her family, she forgave him. She had every reason to kill him when he showed his face at the Western Air Temple. However, she eventually chose to move past things and forgive him. The two would become close friends, and they shared another moment that will be discussed later in the article.
Helped Korra In Her Old Age
Despite being in her late 70s by the time Korra was born, Katara took on the duty of training the new Avatar in her 80s. She didn't need to do this, she chose to. Katara trained two Avatars during her lifetime.
This just goes to show that Katara wanted the best for the entire world. In addition, despite being well into retirement age, she worked to train Korra in the ways of waterbending. And Korra's waterbending skills were unparalleled. All thanks to Katara.
Helped The Earthbenders Escape Prison
The hordes of earthbenders that were trapped in a Fire Nation prison rig were saved by none other than Katara herself. She purposely trapped herself in order to devise a plan to save the group. Eventually, with help from Aang and Sokka, she did just that. This, in turn, led to the earthbenders freeing themselves from Fire Nation jurisdiction. Once more, thanks Katara.
Didn't Use Her Bloodbending Powers
Katara is incredibly gifted when it comes to one dangerous skill, bloodbending. She knew how to use this skill to a scary level, but chose not to use it. Bloodbending would be an easy way for her to, essentially, have all of the power in the world. However, she never used it unless absolutely necessary. She even got the act outlawed in the United Republic. Talk about being for the good of the many.
Pretended To Be The Painted Lady
A Fire Nation village had been abandoned by a spirit that had protected them, the Painted Lady, due to the fact that the rivers that surrounded their village were polluted. In her place, Katara impersonated the Painted Lady in order to help the villagers, who had become sick from said pollution. Eventually, she was able to clean the river of its pollutants with the help of Aang. The real Painted Lady then returned, and thanked Katara for what she had done.
Defeated Azula
Of course, one of the best things that Katara did was step in and defeat Azula once Zuko was struck down. This was an incredibly tense fight, but in Azula's declining mental state, she was able to trick her into walking over a grate of water, which allowed her to freeze the almost-crowned Fire Lord. This, of course, was a huge element of the Hundred Year War ending for good.