One idea could be the emergence of new villains or threats that are not directly related to the previous war. These could be dark forces that were awakened or created due to the chaos of the war. The heroes would then have to come together again, but this time in a different context, where they have to use their post - war experiences and new - found unity to face these threats.
One possible plotline could be about the rebuilding efforts. The different nations might come together to reconstruct the areas damaged during the war. They could share their unique skills and resources. For example, the Earth Kingdom could use its earthbending to reshape the land, while the Water Tribes could help with providing clean water sources. Another plotline could focus on the characters' personal growth. Aang might struggle with his role as the Avatar in peacetime, having to deal with political issues rather than just fighting. Zuko could face challenges in ruling the Fire Nation and trying to change its old ways completely.
Toph would be an important character. Her earth - bending skills and no - nonsense attitude would be valuable in the post - war world. She could help with rebuilding efforts, especially in the Earth Kingdom. Sokka, with his strategic mind, would be another likely main character. He could be involved in diplomatic negotiations and helping to plan for the future security of the nations. And of course, there could be new characters introduced who are the children or students of the original heroes, bringing in a new generation's perspective.
One interesting storyline is Aang's journey to master all four elements. He starts as a young Airbender and has to learn waterbending from Katara in the Southern Water Tribe. This not only helps him grow as a bender but also deepens his relationship with Katara. Another great one is Zuko's redemption arc. He goes from being a banished prince obsessed with capturing the Avatar to realizing the wrongs of the Fire Nation and eventually joining the Avatar to bring balance.
One interesting storyline is about Aang's journey to master all four elements. He faces numerous challenges and meets various characters along the way that help him grow. For example, his time with Katara and Sokka in the Water Tribe where he starts to understand the importance of friendship and loyalty in his quest.
One interesting storyline could be Aang and Zuko teaming up to teach the next generation of benders. They combine their different bending knowledge and ways of life. Zuko could teach firebending discipline while Aang imparts the spiritual side of bending.
The main characters are likely to include Aang, who will be at the center of any attempts to keep the peace. Zuko, who has the huge task of reforming the Fire Nation. Katara, who could use her waterbending and her wisdom to heal the wounds of the war, both physically and emotionally. Then there's Sokka, whose intelligence and creativity will be needed to solve the various problems that arise in the post - war world. Also, Appa and Momo will probably be around, adding a bit of their own charm to the story as Aang's loyal companions in this new phase of their lives.
One popular storyline often involves the main character navigating complex relationships within the harem. For example, Aang might have to balance his duties as the Avatar with the emotions and needs of different characters in the harem. Another common plot is the development of individual relationships, like how Zuko could form a unique bond with a member of the harem while also dealing with his own redemption arc. Some fanfics also focus on the cultural differences between characters in the harem, which adds depth to the relationships and the overall story.
Another way is to focus on the character development. For example, if Zuko from Avatar and Sasuke from Naruto meet. They both have a complex past with a journey towards redemption. Their interactions could lead to mutual understanding and growth. As they face challenges together, they can learn from each other's experiences and apply it to their own personal growth, which in turn helps in merging the storylines.
Well, they might have a whole range of reactions. Aang could be really excited to see different interpretations of his story. Katara might be a bit critical if the fanfiction doesn't do justice to her character. Sokka would probably find some parts really funny and make jokes about it. For example, if there's a fanfiction where Aang tries to learn a new bending technique in a really strange way, Sokka would surely laugh and make fun of the whole situation.
You could try 'The Legend of Korra', which is a sequel and expands on the world and themes of the original. It's got great characters and storylines.