The Twin Serpent Mountains is an area in the Underworld. It is a rugged mountainous area with wondrous sight of two gigantic serpents flowing all through the mountains. One is silver and the other is bronze and their heads are below the monument of Grenth where the Reaper of the Twin Serpent Mountains can be found, once freed. The area is filled with Obsidian Behemoths as well as occasional groups of Charged Blacknesses. The area leads north to the Labyrinth and southeast to the Chaos Planes. The quest Demon Assassin takes place in the Twin Serpent Mountains.