The Underworld.
According to Edgar, it was not always this dreadful and filled with Specters. Before Hades appeared, the Underworld had a different name—the "Mystical Continent". It was different from the Mythical Continent in many ways. It had more condensed Shadow-elements and reeked of Death, making this an ideal place for the Specters to live. After Hades' appearance in the continent, the Specters then gradually unified their strength and became organized.
This in turn made it much more difficult for the other Monsters to live in the Mystical Continent—they either were hunted and killed, or have fled to areas that were far away, or hid in very secluded areas. These survivors had superb survival skills and strength, almost as strong as the "Commanders" in Mythical Continent.
