This large, festering swampland lies in the northern part of The Fang, where the peninsula meets the mainland. It is north of the city of Korgan. The Soldumar River flows through this marsh, which abuts the Dark Sea.
The Holoroon Marsh is said to be home to a host of hostile monsters, including lizardfolk, black dragons, ogres, hags, rakshasas, and nagas. It is also thought to contain the ruins of a palace that belonged to an ancient king of Nerath known as Zartael the Mad.