One popular theme is the exploration of their different worlds. Ed from his alchemist - filled world and Rose from her more ordinary, yet war - torn world. Their relationship can be a way to bridge these two very different existences. Another theme is sacrifice. In the context of the 'Fullmetal Alchemist' universe, both characters have had to make sacrifices, and in fanfiction, this can be explored further in relation to their relationship. Also, the theme of redemption often comes up. Rose has seen a lot of pain and suffering, and Ed, with his quest for the Philosopher's Stone, might see his actions as a way to redeem himself in her eyes and the eyes of the world.
One possible aspect to consider in this fanfiction could be the character development of ED and AL. Their relationship in the original series is very deep and in the fanfiction, it might explore new dimensions of their bond, perhaps in different scenarios or alternate universes.
There are many fanfictions where Ed is portrayed as a girl. Fanfiction writers like to play with the existing characters in new ways. By making Ed a girl, they can introduce new themes and perspectives. For example, it could change how the story deals with gender roles in the world of Fullmetal Alchemist. Also, it can create new emotional arcs for the character, as a female Ed might face different challenges and experiences compared to the male version in the original story.
In a fanfiction, perhaps there's a misunderstanding between Ed and Winry. Winry thinks Ed has feelings for another girl because he's been spending a lot of time with a female alchemist. Ed is oblivious to Winry's concerns at first, but when he realizes, he has to find a way to prove to Winry that she's the only one for him.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). It has a large collection of 'Fullmetal Alchemist' fanfictions, and you can easily search for Ed x Rose stories using the search function. Another option is Fanfiction.net. There are many talented writers on there who write about this pairing. You can also check out Tumblr. Sometimes fans will post links to their favorite Ed x Rose fanfictions or even write short ones directly on their blogs.
In a fanfiction, Ed and Winry could go on a journey together. Maybe they're searching for a rare automail part that could enhance Ed's current prosthetic. Along the way, they face many challenges. They rely on each other's skills - Ed's alchemy and Winry's mechanical knowledge. Their relationship deepens during this adventure as they learn more about each other's dreams and fears.
The fanfiction might introduce new storylines that are not in the original series. It could be something as simple as a day in their lives that was never shown before, or a more complex plot involving new villains or challenges. And seeing how ED and AL react to these new elements is part of the allure.
Another reason is the 'forbidden' aspect of their relationship. Envy is a Homunculus, and Ed is a human alchemist. In the world of Fullmetal Alchemist, such a relationship would be frowned upon. But in fanfiction, this taboo nature makes it all the more exciting to explore. It allows writers to break the norms of the original story and create unique and interesting storylines that involve the two characters defying the odds and coming together in different ways.
There are fanfics that delve into their childhood memories and how those experiences shaped their relationship. For example, the times when Ed was getting his automail fixed by Winry's family. These fanfics often add more depth to their bond and show how their feelings for each other grew over time. It can be really interesting to see different interpretations of their relationship in these fan - created stories.
In a fanfiction like this, Ed dressing as a girl could be part of a bet. His friends might have dared him to do it, and at first he's all about proving them wrong and showing he can pull it off. But then he realizes that wearing a girl's dress comes with its own set of challenges, like walking in different shoes or dealing with long hair (if he has a wig). This could make for an interesting character - development story.