Do not be fooled by the large amounts of dislike, it's mostly people being petty and bullying (In just a few hours with only one chapter it gets 30 downvotes). Give the fic a fair chance.
Thousands of years ago, in Pre-Equestrian times, an evil creature was sealed away within a magical sword that was lost in dimensions.
Twilight Sparkle and her friends soon find themselves caught in a great battle as that evil creeps forth once more, and they are joined by most unusual allies to prevent the two worlds from being shrouded in hatred and chaos unimaginable!