They are popular because Aang is such a beloved character. His death in a fanfic creates a lot of drama and allows for exploration of different characters' emotions. Fans like to see how the other characters would react and grow in the face of such a great loss.
Well, a common theme in fanfiction is their romantic adventures. Fanfic writers love to imagine Aang and Katara going on secret dates to beautiful, hidden places. These could be secluded islands or magical caves. Their relationship in fanfiction can also be a bit more complex than in the original series. There could be misunderstandings due to their different upbringings. Aang being the last Airbender with a more carefree nature at times, and Katara being a strong - willed Water Tribe girl.
One great Aang fanfic is 'Aang's New Adventure'. It takes place right after the end of the series. In this fanfic, Aang has to deal with some leftover Fire Nation rebels who don't want to accept the new peace. It's really exciting as it shows Aang using his bending skills in new and creative ways to bring about peace once again.
One possible 'Avatar Aang death fanfic' could be about how his friends deal with the grief. For example, Katara might struggle with the loss of her love while also having to step up and be a stronger leader in the Water Tribe. Another could focus on how the world changes without Aang's presence to maintain balance. Maybe new benders emerge in unexpected ways to fill the void he left.
One memorable moment in fanfiction could be their wedding. It's often depicted as a grand celebration with all the four nations coming together. The air is filled with joy and the hope for a new future. Another moment could be when they first confess their love to each other in a very private and tender setting, away from the chaos of the world.
Many Aang fanfics offer unique takes on his powers. Some might show him learning new airbending techniques or using his Avatar state in ways that weren't shown in the series. This creativity in exploring his abilities makes these fanfics appealing to fans who want to see more of what Aang can do.
Their relationship could develop through a series of challenges. For example, they could be forced to team up against a common enemy. This would make them start to respect each other's abilities.
Well, a really interesting plot could be a post - war scenario where Aang and Azula are forced to interact due to some political unrest. Aang wants to bring peace and Azula, with her strategic mind, could either be an obstacle or an unexpected ally. Or perhaps a fanfic set in an alternate universe where Aang and Azula are raised together. Their different bending abilities would create a unique dynamic, and we could explore how their friendship or rivalry develops.
One common plot idea is Aang and Katara facing challenges in their relationship due to their different cultural backgrounds. For example, Aang being an Air Nomad and Katara a Water Tribe member.
You can try some popular fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfictions, and you can search for 'avatar aang and katara love' to find relevant works.