When the Necromancers were banished from the Seven Cities after a civil war, they flew into the inhospitable valley of Heresh.
A few years later, the necromancers begun the war of revenge against the new kingdom of the mages, the Silver League or the silver cities, later known as War of the Broken Staff. The necromancers lost the war and Heresh was invaded by the troops of the Silver League.
At the time of Queen Isabel's War and the following years, the Deathlords of Heresh become lazy and didn't care about the war, except one, the necromancer Markal. Later, Lord Arantir, one of the greatest necromancers that ever lived, united the dominions of the deathlords under the Will of Asha and became the "High Lord of Heresh". What happened with Heresh after Arantir's death in Stonehelm is unknown.
Heresh lies near the sea, in which you found some islands like Obiira, on which Raven founded her dominion. The lands of the orcs and the Holy Griffin Empire, but also the lands of the wizards are the neighbours of the necromancers.