The discovery of dungeons has been the task of all civilized races that live above the ground ever since the first dungeon was discovered.
Nevertheless, it has proven impossible to facilitate a unified approach and free sharing of information. All empires, kingdoms, churches, organizations, or aristocratic families that spent time and effort revealing the depth and secrets beneath their feet kept their pieces of information hidden from common perception.
Holding onto snippets of information like family treasure.
Although public information about the world below has been confirmed, enough is known for everyone to have an understanding of the dangers and opportunities that may exist.
A key topic of discussion is the various grades of dungeons, according to the depth and amount of mana they contain.
The highest level of dungeon ever conquered by civilization was disaster grade, with 60 S-class warriors deployed and 200 A-class.