Zilkhûn is an Underdark city of Batwor. It was built by the Khazarkar Empire a half a mile under the empire's capital Nibar-Pharân. This place was built at great expense and use of magic as a rival commercial port to Bandunazân and Balmoloch. A harbor was dug before the city and then a channel made all the way east to where they then broke a coffer dam, letting in the sea waters of Erethor. This created an Undersea port that is linked to the surface. The city along with its sea channel lie inside the great plateau Khirrêth.