Mount Arreat was created by Inarius, shaping the mountain as a protective shell around the Worldstone. It was the first landform created on Sanctuary. The Barbarians buried their warriors upon the slopes of Arreat, and believed that those were denied this would be doomed to have their spirits roam the land for eternity. 20 years after the mountain's destruction, the forces of Azmodan poured out of it to assault Bastion's Keep to the south. However, they were driven back to the crater left behind and defeated.