Well, one possible plot could be that Aang is hit by a strange magic or spell that turns him into a girl. He then has to deal with the new physical form while still trying to fulfill his duties as the Avatar. Maybe he discovers new aspects of the world around him that he didn't notice before as a boy, like different social expectations for girls in the Avatar universe.
There could be an ancient evil spirit that was released when Aang turned into a girl. This spirit feeds on chaos and the disruption of natural order. It sees Aang's transformation as a sign of the world being out of balance and tries to make it even worse. It might target Aang specifically because he is the Avatar and his new form gives it an opportunity to create more disorder.
Aang's relationship with the Air Nomads' spirits could also be affected. As a girl, she might be seen as a new form of the Avatar by the spirits. They could communicate with her in different ways, guiding her on a different path. This could lead to new alliances and ways of using air - bending that were not available to Aang when he was male. Also, her relationship with other female characters in different tribes could become more sisterly, with them sharing secrets and knowledge specific to women.
Well, perhaps in this fanfiction, Aang turns into a girl due to some strange magic or spirit encounter. And then she finds that she can connect with certain female spirits in a new way. This leads her on a journey to understand this new aspect of herself and also use this new connection to bring balance to the world in ways she hadn't considered before.
Yes, if the title 'aang is a firebender fanfic' is to be taken literally, then aang is likely a firebender within this fanfic. However, without actually reading the fanfic, there could be some sort of plot twist or alternative interpretation that might make it not so straightforward.
First, you need to establish the reason for the transformation. It could be a magical spell gone wrong, or some kind of strange dragon - related phenomenon. Then, focus on how Hiccup adjusts to her new body. She'll have to deal with different physical abilities and limitations. For example, she might be physically not as strong as before, but more agile in some ways.
A fanfic could explore how Hiccup's transformation into a girl affects his friendships. Astrid might react in a complex way. At first, she could be jealous or confused, but then they could form a stronger bond. Also, Hiccup's father, Stoick, might have a hard time adjusting to his son becoming a daughter, which could add a lot of emotional depth to the story.
One possible scenario in this fanfic could be that Tony Stark, through some sort of magic or scientific experiment gone wrong, turns into a girl. This could lead to a whole new set of adventures and character developments. For example, his relationships with other characters like Steve Rogers (Stony) would be completely different. He might have to face new challenges in a different physical form, such as how society and his friends would accept him. Also, his own self - perception would change, and he'd have to re - evaluate his identity.
Well, in a 'freed turns into a girl' fanfic, the plot might start with an experiment gone wrong. Freed was perhaps trying to enhance his magic power and something in the experiment caused his physical form to change to that of a girl. He would have to deal with the reactions of his guildmates. Some might tease him, while others would be more understanding. And he would also face challenges like how to adapt to the new body's physical limitations while still being able to participate in guild activities.
The fanfic might also explore how Issei's powers are affected by the transformation. In the original Highschool DxD, Issei has his own set of abilities as a male. But as a girl, he could either have new powers related to femininity in that universe or his existing powers could be modified. This could lead to new battles and challenges where he has to learn to use his powers in a different way.