Pulsing Cavern (Skelator)

Arioch: "To defeat your cousin you must go through the Shade Gate and travel through realms. There you will find Pulsing Cavern, within it lies your salvation. Two black swords, forged by the lords of Chaos many aeons ago, swords that could tear this world in half if used together. They are Stormbringer and his brother, Mournblade."