The Sundering: Rise of the Witch King is a mod for Medieval 2: Kingdoms and based around the fantasy world of Game workshop's Warhammer universe during the civil war between the Elves, the mod's campaign opens with the Death of Bel Shanaar in -2751 IC.
The Sundering v0.6 Part 1 of 4 Instructions: Download all the parts in the same folder and run the executable file. Do not try to mount the .bin files. It is not necessary.