"What you wanna go messin' around up in the mountains for? Ain't nothin' up there but snow, and wolves, and more snow.
Yer lookin' for the old tomb? Take my advice, boys. Let that tomb alone. There ain't nothin up there you ought be messin' with. No money, no treasure, no fame, just ice. And death."
A group that wished to be 'ever-living' instead was cursed with 'never-dying'. Thier flesh rotted and fell fromthier bones but still they lived on. Now as skeletons they continue thier quest to remove thier curse. As skeletons they differ in that they do not need controlled or summoned. They are fully fledged NPCs with drives or ideas of thier own. Stabbing and slashing weapons would not affect them.