Katara, Zuko, and Azula
Here are more art cards based on Avatar: The Last Airbender. In order from top to bottom is Katara, Azula, and Zuko.
Katara is the most challenging because I wanted her to look attractive, but still retain that youthful, kid look. I also played around with her eyes a little bit too, so they don't look exactly how it is in show. I do like her pose a lot.
Azula is probably on the easier characters from the show to draw. She has a very good evil look to her that makes her so distinctive. The most reference I used for Azula was getting her hair right. In fact, I still don't quite understand how her hair works.
Zuko is a pose that I had a perfect idea in my head immediately. I like how crazy action-packed it looks with all of these speed lines radiating off of his fire fist.