When Devil Fruits began appearing on Earth, the world's government's cut all ties with each other and a world war broke out for the fruits. No one was safe, women, children, and even the elderly were shot down all for simply holding a Devil Fruit. Orphans had nowhere to turn until they found or were found by The Devil-Devil Club, a resistance group of kids and teens orphaned by the war, trained to fight with either Devil Fruits or weapons.

But when Devil Fruits began to not appear after the eater's death and they begin to become as rare to find as they were in One Piece, a raid on The Devil-Devil Club's home base is caused after the club steals 3 high ranked Devil Fruits, The Gum-Gum Fruit, The Tremor-Tremor Fruit, and The Flame-Flame Fruit. The Devil-Devil Club's only survivor and founder, Jake Law, eater of the Op-Op Fruit, ends up in Equestria after fleeing from the armies after the 3 fruits he had taken.

Thanks to Pseudo Brony for letting me use some of his Devil Fruit Ideas from this link here and editing the chapters!