One idea could be that the characters from Fire Emblem: Three Houses are magically transported to the wizarding world of Harry Potter. They could be sorted into Hogwarts houses based on their personalities. For example, Edelgard might be a Slytherin as she is ambitious and a natural leader. Then they could learn magic and help the students of Hogwarts in a battle against a new dark wizard threat, using their unique combat skills from their own world in combination with magic.
One great fanfic could be 'A New Bond'. It really delves into the relationship between Dimitri and Byleth. It shows how they support each other during battles and in the political intrigue within the game's world. The author does an excellent job of portraying their growing feelings for each other in a very natural way.
A great plot for a crossover fanfiction could be a time - travel crossover. Fire Emblem Three Houses characters travel to the future or the past of their own world but with a twist - the world has elements from other universes. So they might encounter mechs in their otherwise medieval - like world. Or they could cross over with a high - school anime setting. The students would be in a normal high - school environment but with their Fire Emblem abilities. This could lead to some really fun and comical situations like using magic in a science class or sword fighting in the schoolyard. Also, a crossover with a post - apocalyptic world would be interesting. They would have to deal with new threats like radiation and mutated creatures while trying to maintain their own values and relationships.
One reason could be the complex plot that may be hard to follow for some players. There are multiple routes and a large number of characters with their own backstories, and it can get jumbled up.
It depends on personal preferences. Some might think the Blue Lions' story is the best for its focus on honor and loyalty. Others might prefer the Golden Deer's story for its strategic elements.
The story of Fire Emblem Three Houses can take a significant amount of time to complete, depending on your playstyle and how much you explore. Roughly, it could take around 50 to 80 hours.