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Original Description:

When the crystal empire returned, it brought king Sombra back with it, Equestria was brought to a dark war, fillies who were unlucky enough to be caught out of their homes were forced into the crystal empire to be trained, Twilight was one of the fillies to be caught, for years now she had been a working unicorn, her horn broken by the procedure of usurping of her magic, Fluttershy, a mare who was willingly joining Sombras army, was sent to train Twilight before she was ready to send supplies to the soldiers on the battlefield against Canterlot.
EQUESTRIA’S WAR: Friendship Ends