The Undead Region is the region where the undead characters start. You can visit this region only if you are undead or if you reach level 30.
The region is composed of 6 areas. The first area is Necrolis (the Undead starting city), then Land of Bones, Forest of the Fallen, Soulmoor, The Badlands and Crystaline Crypt. Each zone is more difficult than the previous.