This will be a Fire Emblem 7 Crossover [Although the only time Humans are in the story are though memory flashbacks]

Every now and then souls are reborn in a new body, but if the new body touches something important to the soul, there is a chance ancient memories will re-emerge

Follow the story of the Cutie Mark Crusaders who find three weapons in a hole on the Apple Family's orchard

[Alternate Universe Tag] For in this story its implied that the land of Equestria was once the land of Elibe