Avatar Katara was one of the first fanfictions I really got invested in, and it's grown a lot since I first wrote it in high school. I've taken a lot of the characters that were in the first series and expanded them to create a new story based around Katara as the Avatar.
Katara has always been my favorite character, and I think a large part of that stems from the problems I have with Aang. Namely, he's way too light about the war in the early episodes. I understand it, of course, he didn't grow up with the war like Sokka and Katara did. Yet, I wondered how Katara, who was extremely protective of the people she cares for, would do as the Avatar. She would certainly take it more seriously than Aang did at first, and I really enjoyed exploring that concept.