Black Grill's Cave is an extremely huge 'infrastructure' whose origin and creation are unknown by the general populace. This means that not only the players but also the NPCs, don't actually know the history nor origin of this place.
The earliest tales of the Cave system was that of its discovery. Back then, the Fallen Heart Kingdom had yet to exist and there was only a low-level independent settlement of humans close by. The humans in the settlement decided to explore the grounds but in the process of doing so, they lost a lot of men. Eventually, they left the lands unclaimed and unexplored, focusing on their usual daily lives and activities. The only noteworthy achievement the village did was tagging the site as a forbidden ground.
[1] Unless in special occasions or if they are heavyweights, merchants don’t drink so as to avoid an erroneous transaction under the influence of alcohol.
Infinite Facts :
An Infinite Mortal is one who has the attack power and abilities of a demigod but lacks certain requirement to be a true one. Based on this, it could be said that an Infinite Mortal was weaker than a demigod but in a life-or-death battle, it is actually a 50-50 chance of victory or defeat for both.
Infinite Facts 2 :
The caravan head, Black Grill, was actually held hostage by a few radical villages but on the threat that he had special letters with the information ready to be distributed to every possible figure, the villages would let him go. To also butter up to them, Black Grill would claim that he will only sell the information at a much higher price to others if at all, any village that captured him, suspected him of trying to reveal this ‘secret’ information.