"A Dungeon," Compass Carburettor frowned, asking, "Is the Heroica Empire ignorant about this Dungeon?"
"Y-Yes," The Boss said, "Since the Grogar are a troublesome enemy, the Empire has never ventured deep into their territory. So, they haven't spotted the Dungeon yet. Had they discovered the Dungeon, they would have poured all their resources to eradicate the Grogar and occupy it. Even though it is only a Level 1 Dungeon, it hasn't ever been raided by humans. So, the amount of Darble Crystals it has accumulated over the countless years since its existence should be an enormous sum."
Having read enough documents about Darble during this time, Compass Carburettor was aware of how they formed. There didn't exist any mine in nature that produced Darble. As explained before, the only source of Darble was the Dungeon monsters.