It is said that that's the place where the very ancient civilization and the thrones of the god remains, and all the wisdom of nine worlds in the legend still sleeps. Since it is unknown when the castle exists, the mural painting drawn 5,000 years ago still has such a record. The mages who took care of this castle were called Melgalian (メルガリアン Merugarian?).
It's also said that among those who approach the mystery of this castle, there are so many unnatural things that suddenly disappear or become dead.