In Avatar: The Last Airbender, many deep themes are explored, from forgiveness (especially between Zuko and Iroh), how absolute power can corrupt (such as princess Azula), learning to move on from grief, and much more. Katara of the Southern Water Tribe was connected to many of these themes, and they shaped her character arc.
Katara didn't change as much as Zuko did over the course of three seasons, but she did undergo some subtler changes that showed her maturity and understanding of the world. Not only did Katara learn forgiveness by accepting Zuko as a friend, but she learned to have a wary and cautious relationship with power of any kind.
Katara's Early Forays Into Power
Katara was never a power-hungry sort of person, but then again, she was arguably the strongest hero of Book One: Water, until the very end of that season when the Gaang arrived at the Northern Water Tribe. Katara was the only Waterbender in her tribe, and she was anxious to learn more about this art so she could protect her tribe and family. Then, when Aang was released from the iceberg, Katara took it upon herself to escort him and Sokka to the Northern Water Tribe, across the entire globe, to help Aang learn Waterbending. Along the way, Katara offered to teach Aang what she already knew, to give him a head start.
During this time, the Gaang was constantly on the run from pursuing Fire Nation forces, and the Gaang even visited an island territory of the Fire Nation itself. Katara wanted to fight back by any means, and she boldly took it upon herself to be a hero and dive into any situation or battle against the Fire Nation. Most significantly, Katara resorted to theft; she found a rare and valuable waterbending scroll in the possession of a pirate gang, and she swiped it from them. Aang was shocked, but he and Katara went ahead and made use of it, and Katara used some new techniques to help fend off both the pirates and Zuko's gang. Katara had a questionable opportunity and seized it, but later in the series, she would change her position.
The Strength To Not Use Strength
Katara wasn't on a slippery slope toward villainy, but then again, she later clearly defined her relationship to power, more so than in Book One. More specifically, "can" doesn't always mean "should," and this will put Katara at odds with other people and even herself at times. And every time, Katara took the high road and bettered herself as a person for it. One example was when she met Hama, an elderly Water Tribe woman living secretly in the Fire Nation itself. A Waterbender, Hama had been captured and then devised bloodbending as a means of controlling other people during the full moon. Hama taught this skill to Katara, but Katara soon learned that Hama had been abusing this power to torment the townsfolk in retaliation for her earlier capture. Disgusted, Katara used bloodbending exactly once to subdue Hama, then swore to never perform this mighty art again, even though she was fully capable of using it to great effect. In fact, Katara would later formally outlaw the use of bloodbending, an act that future mobster Yakone would protest. During the course of the Hundred Year War, Katara learned that not every weapon should be wielded. Some powers came at the cost of corruption and a loss of justice and honor.
Similarly, Katara later was in a position to finally dispatch her mother's killer, a retired Fire Nation commander. At first, Katara brushed aside Aang's protests to this revenge plan, but when Katara and Zuko cornered the hapless old man on a rainy countryside road, Katara hesitated. She had the power to skewer the old man alive with her icicles, but would this power bring her peace and happiness? It wouldn't. Katara was better than that, and she realized it at the last moment. As Zuko watched in awe, Katara released her waterbending and left the confused old man shaken but alive. When she returned to camp, Katara admitted to Aang that he had been right. Katara was now stronger and more experienced than ever, but unlike that time she stole a waterbending scroll, she refused to exploit her abilities or fight dirty. After leaving the remote confines of the Southern Water Tribe, Katara was exposed to the big wide world and its many dangers and powers, and she realized that justice is not always delivered by the hammer. She would keep this lesson well into her elderly years.
