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.
He could meet his future self. It would be an interesting encounter as he could learn from his future experiences and wisdom. Or he might meet people who have studied his past adventures and see himself through their eyes.
He might start by observing. Aang is a curious person, so he'd likely watch how people live, how they interact with technology. He may also try to find other benders to learn about any new developments in bending. And he'd probably use his kind heart to make friends easily in this new future environment.
In some fanfictions, Aang's connection to his past lives plays a crucial role. He could draw on the wisdom and skills of previous Avatars. They might guide him on how to defeat Azula specifically. He could learn a new bending technique from one of his past lives that gives him an edge over Azula's firebending, like a unique way of using water to extinguish her most powerful fire blasts.
Well, Aang being the Avatar has a deep connection with the elements. In this fanfiction, perhaps he enters the Avatar State and uses all his elemental powers in harmony. He could use waterbending to create moisture and cool the volcano, combined with his airbending to disperse the heat and gases.
Sokka would also be a common character. His strategic mind could be very useful in a different time period. He might be the one who figures out how to deal with the new situations they encounter while in the past. For instance, if they need to outwit an enemy in a historical battle, Sokka would be the one to come up with a plan.
In some fanfiction, Aang's tattoos might be depicted as glowing with a special power when he reaches a new level of understanding or connection to the Avatar state.
Aang could be friends with Neville. Neville is often underestimated but has a lot of courage, just like Aang. They could bond over their shared experiences of being different. Also, Luna Lovegood might be interested in Aang's unique abilities and his different world view, so she could be a potential friend too.
In non - lemon fanfiction, Aang is often portrayed as his kind - hearted self, trying to bring peace and balance. He might be shown using his airbending skills in creative ways to solve problems or face challenges. Azula, on the other hand, is usually depicted as a complex character. Her intelligence and powerful firebending are emphasized, and she may be in a journey of self - discovery, either trying to redeem herself or continue her pursuit of power in a more nuanced way.