Broken Spine

The peaks of the Broken Spine are but foothills in comparison to the Worlds Edge Mountains, but they form no less a barrier to evil. Without them, the eldritch winds that blow through Sylvania would carry armies of the dead further into Stirland, the Moot, and perhaps even across Aver Reach. As it is, the fell winds are contained by this hinterland, and many powerful Undead with them.

Source

 * : Sigmar's Blood
 * : pg. 7