Advigar

Advigar is a region in Galben, Nova.

An ancient dwarven fortress called Diamaria is built into the mountain here that's been abandoned for hundreds of years. The dwarven king grew greedy for precious ores and ordered his people to carve long, winding tunnels through the mountain, creating an infinitely complex, unplanned layout. As his dwarves dug deeper, they eventually broke through to the Underdark and were enslaved by Mind Flayers. This legend is known among the dwarves and causes them to fear digging too deep. The dwarves escaped and are now Duergar. They have continued digging deeper and built a second fortress under the first, but few people know of this. They are sometimes seen wandering lower levels of the first fortress, along with some other creatures from the Underdark. The upper levels hold many beasts and monstrosities they have made the convenient, abandoned space their home. This is the main entrance to the Underdark in Nova and a significant Underdark dweller (normally an outcast) will enter the outside world and make a lair of their own (or usually take over an existing one from another creature).

However, this information is largely not known by most of the population. This region is known for the goblins that hold the land, and the goblin king Great Grumble regularly holds competitions and quests for visitors to kill particular creatures or retrieve valuable treasures from Diamaria. Great Grumble hordes treasures and uses his quests as a win-win for more treasure, where he usually attempts to give minor rewards in exchange for great treasures (unknowing to the adventurers). If they fail, he sends a number of goblins in on a suicide mission to retrieve the belongings of the dead adventurers so that he can add to his collection.