Diablo 2 

In the sequel, it turns out that fixing Diablo's Soulstone to their forehead and absorbing his essence wasn't really the best idea. The hero of the first Diablo has become corrupted by the Lord of Terror, bringing more demons into the world and continuing Diablo's chaotic reign from the first game Diablo 4 Gold. The possessed former hero, now known as the Dark Wanderer, is also attempting to free Diablo's other brethren, Mephisto and Baal.

Once reunited, the three open a portal to Hell, but the protagonist manages to defeat Diablo and Mephisto and destroy their Soulstones to prevent them from returning once more. In the expansion Diablo 2: Lord of Destruction, Baal is the last surviving Prime Evil, and after obtaining his own Soulstone from Marius he attempts to corrupt the Worldstone. This weakens the boundaries between the realms of Heaven, Hell, and the mortal world of Sanctuary.

Diablo 3 

Over a decade after Diablo 2, the next entry Diablo 3 was released. Players return to the world of Sanctuary twenty years after the events of Diablo 2 and its expansion. Deckard Cain, a prominent NPC in the Diablo series who guides gamers, is back as he explores Tristram Cathedral in search of answers about a prophecy before a falling star hits the building and creates a crater into which Deckard disappears. After investigating the crater and saving Deckard, players find the Archangel Tyrael and help him to restore his lost memories.

Appalled by the apathy of his fellow angels toward the plight of humanity and the plague of demons in Sanctuary, Tyrael chooses to become mortal so that he can help warn humans about the arrival of the Demon Lords. Players must counter the demonic forces and search out the Black Soulstone, which has the power to imprison the souls of all seven of the Lords of Hell. However, the player and their cohorts are betrayed and the Black Soulstone is used instead to resurrect Diablo with Leah – Deckard's ward – as his vessel. Diablo now has all the souls of the Lords of Hell within him and begins his assault on the High Heavens. Diablo is eventually defeated and Tyrael remains in the High Heavens, determined to forge a greater bond between them and the mortal realm buy Diablo IV Gold.