Introduction to the First Dungeon located on the Island Called Hidden Terrors.
The dungeon essentially is where the school dumped the students that suffered received physical and mental damage from being frozen for too long. Though most have actually died off as a result of their powers there are a few that still roam around which makes the first dungeon not as straightforward as one would expect.
Dungeons are mysterious buildings that have just started appearing around the world. Rumor has spread that whoever conquers a dungeon gains great riches and power. Not much besides that is known to the people of all the countries.