World Stone

The World Stone is an object in the popular game Diablo II, made by Blizzard Entertainment. The Worldstone is a massive crystal located in a cavern in the middle of Mount Arreat. Its purpose is to prevent the Burning Hells and the High Heavens from consuming Sanctuary into its respective folds. Additional properties of the Worldstone were elaborated upon in the Diablo: Sin War trilogy books.

The Worldstone in Diablo 2

In Diablo 2, your character travels to Mount Arreat to prevent Baal from getting to the Worldstone. Your character finds that he has already gotten there, and tainted the Worldstone in the process. After defeating Baal, Tyrael appears, and tells the character it would be better to have no Worldstone than to have a tainted one. Your character leaves through a portal, and Tyrael destroys the Worldstone.

The Worldstone in The Sin War

Introduced in book two of The Sin War trilogy, Scales of the Serpent, the Worldstone acts as not only a force to keep the High Heavens and Burning Hells from finding Sanctuary, but also to keep the nephalem's powers dampened. Uldyssian ul-Diomed uses his edyrem powers to change the very core of the Worldstone, making it enhance the powers of the nephalem instead of dampening them. This surprises both Inaruius and Rathma, neither believing that such a thing was possible.