The Void.
A place filled with monsters of the deep.
This place was the place where all the monsters who were going to taint the landscape were to be kept. Unfortunately, one of them figured out how to escape by displacing the spell that was cast upon by the creator of the universe. Our only hope for Equestria's survival is one who will be the master of them all, the one who knows how to combat any monster who tries to face him.
That pony you might ask?
That, stallion, is Clear Thought.
"I hope you're thinking clearly, or you'll lose your thoughts on life." -Creed