Diablo V Wiki

In Diablo V the Lord of Terror has already won. He rules Sanctuary from the throne of Westmarch, is present from the first moment of the game rather than waiting at the end of it, and treats the fallen world as a stepping stone to invading the Heavens.

The Heir to Westmarch is the player character of Diablo V, a fugitive in a fallen kingdom who carries a mysterious bond with Diablo that is both an insight into him and a vulnerability to him.