By far the best boss fight in Diablo 4 is against the Guardian of the Cathedral of Hatred, Astaroth, whom players will face as the boss of Diablo 4's second Act in the region of Diablo 4 Items Scosglen. After Lilith frees the lieutenant of Mephisto from his prison in the Soulstone, Astaroth seeks his revenge on the Horadrim who imprisoned him and sets his sights on terrorizing Donan and...