There is one lesser-known tale of the two sisters from the olden days of Equestria, far back before Nightmare moon. When the two Princesses had used the elements of harmony to banish countless dark entities from their world. about a monster who lived in a stone book, and the poor creature it had corrupted to do it's bidding. Each being was different but all were dealt with by almost the exact same method, the Elements of Harmony. But the Elements didn't always do the same thing to every villain it came across.
Forced to be reborn over and over again with his memories intact, earning redemption has never been more painful.