Perhaps it's a story where Naruto has the same kind of tragic backstory as Edward. Maybe Naruto loses Sasuke in a way similar to how Edward lost his mother and brother's body. So Naruto starts to study alchemy in the hope of getting Sasuke back. Along the way, he meets Edward and they learn from each other's experiences and fighting styles, and together they face the challenges in both their worlds.
Yes, there are likely fanfictions out there with such a concept. The worlds of Naruto and Fullmetal Alchemist, where Edward Elric comes from, are quite different, but that's what makes the idea of a crossover in fanfiction so interesting. Writers might explore how Naruto's ninja world and its unique powers could interact with Edward's alchemical abilities and the complex world of Amestris.
Well, it could mean Naruto would adopt Edward's sense of fashion. He might start wearing long red coats and black pants, just like Edward. In the fanfiction, Naruto could also learn about Edward's moral code. Edward has a strong sense of right and wrong when it comes to alchemy, and Naruto could use that to re - evaluate his own actions as a ninja. Maybe he would be more cautious about using certain jutsus that have a high cost or moral implications.
One possible outcome is that Naruto would gain a different perspective on alchemy. Edward's scientific approach to combat and his understanding of equivalent exchange could influence Naruto's way of thinking. Naruto might start to analyze his jutsu in a more methodical way, similar to how Edward approaches alchemy. For example, he could consider the energy input and output of his shadow clone jutsu more carefully.
Edward might meet his parents. Since he has the chance to go back in time, he could meet them when they were alive and perhaps learn more about alchemy from them, which could change his future actions.
They could start by comparing their different worlds. Edward would explain about the principles of alchemy like equivalent exchange, while Urahara would talk about the Soul Society and the way spiritual power works. This exchange of knowledge could be the foundation for their relationship in the fanfiction.
Well, often there's a theme of adaptation. Fem Edward Elric has to adapt to the Naruto world's way of life, its politics, and its combat system. Also, the theme of power - sharing is common. They could combine their skills, like Edward's alchemy and Naruto's ninjutsu to defeat a common enemy. And sometimes, there's a theme of identity, as Fem Edward Elric might question who she is in this new world.
One interesting fanfiction could be where Naruto and Edward Elric team up to fight a common enemy that has elements from both their worlds, like a chimera made of shadow clones and alchemy - based creatures. They'd use Naruto's ninja skills and Edward's alchemy in unique combinations.
One possible plot could be that Edward Elric discovers Ki as a new form of energy. He might initially struggle to understand and control it, like he did with alchemy. He could meet a mentor who teaches him the basics of Ki, and then he uses this new knowledge to face his enemies in a different way, perhaps even combining Ki with his alchemy skills.
Well, perhaps Edward could use his alchemy skills in the magical world of Hogwarts. He might be sorted into Gryffindor for his courage. He could start to learn magic along with the Hogwarts curriculum and have some interesting interactions with the students like Harry, Hermione and Ron. Maybe he'd show them some unique alchemy tricks and in turn learn some new spells.
In some fanfictions, Edward Elric might gain the ability to manipulate time. This could be a really cool addition as it would allow him to go back and correct mistakes he made in his past, like the failed human transmutation that cost him his arm and leg.