Hell
From Grimhaven Wiki
Hell is a custom map. Located very far north of the town Rissne.
You can access it by entering Thais depot and go down a floor there you will find a teleport.
The Hell is also home to the Fires From Below Quest.
Creatures that can be found here:
Fire Elemental, Fire Devil, Dragon Lord, Dawnfire Asura, Fury, Shaburak Prince, Shaburak Lord, Askarak Prince, Askarak Lord, Diabolic Imp, Retching Horror, Undead Dragon, Hellfire Fighter, Dark Torturer, Hellhound, Warlock, Demon, Orshabaal.
For more information about where check out Spawns.