The Sorcerer's Prison is a tower-like prison that rises up from the center of Eiriwal, the school of magic in Daan. It hosts ten floors above ground and one hundred seventy-five below, It was originally much smaller, as it was an add-on watchtower for the city, but when Sol Almerian was to be captured, the Grand Mages used magic to extend it deep into the subterrain. At first, that was all it was - a place where the horrific Grand Destroyer could be housed safely in his magical prison.
In the years after his capture, the otherwise empty tower was adjusted so that it could be turned into a prison strong enough to house the worst of the worst in the magical community. Only the most dastardly of creatures wind up below the fiftieth floor or so, and there has been some controversy over whether or not putting these evils in close proximity to someone like the Destroyer is a good idea, but the magisters usually argue that there's not much other choice.