Walktrhough Act IV

Trigger : Talk to Tyrael.

Goal : Find and kill Izual in the “Plains of Despair” just after the “outer Steppes”.

Quest reward : + 2 skill points by talking to Izual’s ghost and returning the quest to Tyrael.

Trigger : Talk to Cain after finishing the first quest.

Goal : Destroy Mephisto’s soul stone with the “Hellforge Hammer” from “Hephastos the armorer (mini boss) in the “Hell forge” which is located at the “River of Flame” after the “Plains of Despair” and the “City of the Damned”.

Quest reward : Gems and a rune will fall to the ground after breaking Mephisto’s soul stone placed on the forge.

Trigger : Talk to Tyrael after finishing the other two quests or move on after the river of flame to access the “Chaos sanctuary”.

Goal : Kill Diablo. To do this, you must activate all the seals in the “Chaos Sanctuary”.

Quest reward : As Diablo is an end of act boss, he can drop unique items.

Well done, you’ve finished Act 4 and taken out Diablo, now all you have to do is go after Baal in Act 5.