The legend of the goblin city

It is said among the tribes of this land that in the most ancient times, the oldest prophet-leaders of the goblins, called Darrmu, created a vast labyrinth under the Great Mountains. At its center stood what they called the Earthly Garden of Delights. This was their most secret abode and refuge between Augea and Vetia, protected by the monstrous creatures of the deep - the gogyag.
No man, elf or dwarf was allowed to enter such a secret and holy place, the goblin city. It was imagined as a mortal representation of the Divine Garden that all faithful goblins hope to enter - either after their death, or through transcendental use of the unknown substances they employ in their rites. It is said that denizens of this city would undergo the cruelest challenges if ordered by their darrmu, exhibiting a fanatical faith in some form of Truth which they associate metonymically with these same substances, and with the Twin Deity who supposedly discovered them.