Humanized Equestria

Cold. Dark. There was no light underground.
Rowan had had sixteen thousand years to contemplate his crimes. He knew that what he had done was wrong. But not even a being as powerful as he could change the past. Although, something about his crystal prison had broken his mind, he can remember little from the time before his imprisonment. But when he is released and thrust into the modern world, can he piece together his shattered past, in time to save his new world from a looming threat?