Discord

Discord is the primary antagonist, of My Little Pony: Friendship is Magic.

Princess Celestia and Princess Luna had imprisoned him in stone with the Elements of Harmony over a millennium ago. But when the Elements are transferred to Twilight Sparkle and her friends, Discord escapes from his stony prison and starts to wreak chaos. As his first move, Discord steals and hides the Elements of Harmony and offers a challenge in the form of a riddle as the only hint to their whereabouts. Twilight Sparkle and her friends agree to play by his rules and venture off to retrieve the Elements of Harmony in order to stop him.