Sokka might be a rescuer. He's Katara's brother and he would stop at nothing to save her. He could use his strategic mind and his trusty boomerang to take on the kidnappers. Another potential rescuer could be Zuko's uncle Iroh. He has great wisdom and his own firebending skills. He might be able to outwit the kidnappers and free Zuko and Katara. There's also the possibility of some unexpected characters from their past coming to their aid, like some of the Freedom Fighters they met earlier in their adventures.
One interesting plot twist could be that the kidnappers turn out to be working for an old enemy of Zuko's family. They initially thought it was just a random act of villainy, but as the story unfolds, they discover a deeper conspiracy aimed at destabilizing the Fire Nation. Another twist might be that Katara discovers she has a hidden power that she can use to help them escape, but using it comes with a great cost. Maybe it drains her life force or has some other negative consequence.
Zuko's complexity makes him so interesting in these fanfictions. He has a troubled past which has shaped him, but he is constantly evolving. His ability to show vulnerability in front of the reader is another great trait. It allows for a deeper emotional connection between him and the reader, as seen in stories where he opens up about his insecurities and fears.
Some fanfictions explore their role in rebuilding the world after the war. Zuko and Katara could be working together to restore balance between the nations. This kind of fanfiction often shows their leadership skills and how they complement each other.
In such a fanfiction, Hakoda might comfort Zuko by sharing his own experiences of loss and hardship. He could tell Zuko about how he coped when his tribe faced difficulties. For example, Hakoda might say that even in the darkest times, there is always a glimmer of hope. And that it's important to focus on the good that can come from difficult situations.
In 'Ozai Hurts Zuko' fanfictions, Zuko develops by facing his inner demons. The harm from Ozai makes him re - evaluate his life. He might become more empathetic towards others who have suffered, and this changes his outlook on the world. He also gains a new sense of self - identity, separate from what his father wanted him to be.
There's a possibility that Zuko would meet his grandfather. His grandfather's actions and decisions might have influenced the path the Fire Nation took towards war. By meeting him, Zuko could try to sway his grandfather's views and change the future of the Fire Nation at its root.
Zuko's hot - headedness can be contrasted with Mako's more level - headed approach. Zuko might be quick to jump into action or get angry, while Mako thinks things through. As they interact, Zuko can start to adopt some of Mako's calmer ways, and Mako can learn to be more assertive from Zuko. This development can be shown through various adventures they have together, like facing a common enemy or solving a mystery.
Zuko can be developed by exploring his role as a leader within the context of his marriage. He may struggle to balance his duties as Fire Lord with his time for Mai. This internal conflict can show his character's depth. He could also develop new bending techniques influenced by his love for Mai. As for Mai, she can develop by getting involved in more political matters, standing by Zuko's side and using her intelligence to influence decisions. She could also start to make more friends in the palace, which would change her somewhat solitary nature.
In fanfiction, Ozai's actions towards Zuko can be extremely cruel. Ozai has often been depicted as an abusive father. He burned Zuko's face, which is a very traumatic event for Zuko. In fanfiction, this relationship might be explored further, showing Zuko's struggle to overcome the psychological and physical harm caused by his father.