The world is torn by war being made by Diablo, the demonic lord of terror from Hell itself. With his brothers, the Satanic manifestations Mephisto and Baal, Diablo wages war on the mortal world. However, holy warriors and rebels, along with the help of a celestial Archangel sent by Heaven, stand against Diablo and his malignant forces as they prepare to fight in the truly apocalyptic conflict. In the expansion, Baal takes over command of Diablo's forces as the end of the war draws near.