Gruthren the Excessive (also known as Gruthren Lord of All That Shines and is Buried, Gruthren the Obsessed, Gruthren Master of All Things Great and Small, Gruthren The Builder, Gruthren the Immense and Gruthren Of Too Many Titles) had this great hall constructed on level 3 of a local dungeon that he had cleared out by a team of mercenary adventurers. Purely so he would have something this insanely big for others to discover. Once the reconstruction of the level was complete, he abandoned the site and encouraged it’s repopulation with various foul beasts by leaving behind a significant quantity of gold, gems, foodstuffs, and even some mighty magical treasures he had accumulated.
Sure enough, his plan worked, and foul beasts moved in from below and above, warring over control of the hall in the centre of the dungeon. Finally a potent mind controlling beast took residence here and used one of the magic statues left behind by Gruthren the Foolishly Brave as a magical link back to him, and drew him here to meet his doom.
Well, that’s the story at least. Others say that Gruthren died choking on a chunk of overcooked mutton at the local whorehouse, and the stories of his luring back to the Great Hall was just to conceal how much treasure his advisers and staff took with them when they vacated his palace.
(Originally drawn in 2014, resampled and cleaned up with added grid in 2018)