It could be an ancient dark ninja who wants to use Naruto's new 'avatar of death' powers for his own evil purposes. This ninja might have been researching death - related jutsus for years and sees Naruto as the key to his ultimate power.
One idea could be Naruto having an encounter with a death - like entity that grants him new and dark powers. He might struggle with the morality of using these powers while still trying to protect his village.
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.
Harry Potter himself could be a potential Avatar of Death. Given his connection to Voldemort and all the death and sacrifice he has witnessed, he might develop some sort of connection to death in a more profound way. It would be a very dark and different take on his character, but it could also add a whole new layer of depth.
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.
A 'death of naruto fanfic' could potentially explore many dark and emotional themes. It might focus on the death of Naruto, which would have a huge impact on the entire Naruto universe. His friends and family would be devastated, and the village he protected would be in chaos. It could also be a story about the death of the idea of Naruto within the fan community, perhaps due to changes in the way the story is perceived over time.
It could be a great fanfic. The idea of mixing Naruto and Avatar has a lot of potential. If the fanfic delves deep into character development within this new combined world, it would be amazing. For instance, how would Naruto react to the concept of the Avatar state? And how would the Avatar characters view Naruto's determination and his way of protecting his friends? If the fanfic answers these kinds of questions in an engaging way, it has a high chance of being a good one.
Perhaps in this 'emperor naruto avatar fanfic', Naruto is made emperor due to his heroic deeds in both worlds. As emperor, he has to deal with political intrigue. He might have to form alliances with different clans from the Naruto world and different tribes from the Avatar world. His friends from both universes would help him, like Sasuke and Aang. They could teach each other their unique skills and fight against common enemies who oppose Naruto's new rule.
I'm not sure specifically as it could cover a wide range of things. It might be a fan - made story that combines elements from Naruto and the concept of kami (gods) in an avatar - like form. Maybe it has a character who has the powers of a Naruto character and also some sort of divine avatar powers.
Perhaps in this fanfic, Naruto would be confused by the concept of the Avatar at first. But as he gets to know more about it, he realizes the similarities between his world and the Avatar world in terms of protecting people. He might also have some interesting interactions with the different tribes in the Avatar world, like the Fire Nation. And who knows, he could even find a way to use chakra to enhance bending abilities.