Lord of Destruction (Act)

Lord of Destruction is the fifth and climactic act in Diablo II, added when installing the Diablo II: Lord of Destruction expansion. It is named after the Prime Evil Baal, the Lord of Destruction, whose trail the player follows to the lands of the Northern Steppes.

Summary
After going through the portal that Tyrael opens after Diablo's defeat in the Chaos Sanctuary, the player arrives in Harrogath, the Last Bastion of Order on the slopes of Mount Arreat, in Malah's own words. Initially, no one except Malah, believed the player to be of any use in the ensuing conflict against Baal's Demonic Legions other than being cannon fodder for the Barbarians, especially the last surviving member of the doomed Council of Elders, Nihlathak.

But the player quickly proves his worth when he bests one of Baal's strongest generals, Shenk the Overseer, in combat, finishing the Siege on Harrogath quest. Larzuk the Blacksmith offers to socket one of the player's items as a reward, a service not normally given to anyone.

Qual-Kehk warms up to the player but still wants him to prove his worth. He sends the player out in the Frigid Highlands to rescue some of the Barbarians who have been held captive by Baal's forces. Soon, the player finds that the very fortifications that the Barbarians built to hold the demons at bay are being used against the Barbarians themselves by the Legion. The player is successful in rescuing the captive Barbarian Warriors and the player earns Qual-Kehk's trust, who allows some of his men to aid the player in his quest. As news of the player's exploits spreads, Malah requests the player to aid her in something that was prodding her mind, the daughter of the Head of the Council of Elders, Anya had disappeared. And she feels that Nihlathak is responsible for her disappearance. The player follows Malah's clues to the Crystalline Passage, where he finds Anya trapped in a prison of ice. Anya is rescued but Nihlathak goes missing.

Anya explains Nihlathak's real plans to give Baal the Relic of the Ancients to spare Harrogath. But in doing so, Nihlathak has allowed Baal to pass into the Worldstone Keep unhindered. There Baal hopes to corrupt the blessed Worldstone, an act that would utterly doom all of Sanctuary. Baal was to meet Nihlathak at his temple. So, the player follows him, trying to stop the traitor from dooming the world. After finding Nihlathak and defeating him, the player searches his lair for the Relic, but does not find it. Baal already has it and rushes towards the Summit.

The player follows Baal and meets the Ancients, spirits of the Nephalem. After a great fight, the Ancients are bested and the hero proves himself worthy. The Ancients allow the player rightful passage to the Worldstone Chamber.

But Baal was already inside the chamber waiting for the player. Taking a cue from his fallen brother, he summons his finest Warriors from beneath Hell. The melee inside the Worldstone Chamber ends in Baal fleeing inside the heart of Arreat itself, where the player battles the Lord of Destruction ending the reign of the Prime Evils over Sanctuary. Tyrael appears, informing the player that Baal, although defeated, succeeded in corrupting the Worldstone. The stone now drains the world's energies, weakening the boundaries between Sanctuary and the Burning Hells. This would allow the hordes of Hell to spill forth into the mortal realm unhindered.

Tyrael, after allowing the hero to reach safety, proceeds to destroy the Worldstone. The resulting explosion causes Mount Arreat to erupt, destroying the homeland of the Barbarians, and causing some damage to a nearby keep.

Epilogue
Though the Prime Evils are no more, everyone fears for the future. A demonic invasions seems imminent, now that the boundaries between the realms have weakened. Years go by, yet nothing happens.

Twenty years later, has it really ended?

Quest Necessity and Tips
For one to end Baal's reign of Destruction and progress to the next Difficulty level, he/she must complete the Arreat Summit and Eve of Destruction quests, although the other quests reward your deeds in the following ways:
 * Completing the Siege on Harrogath rewards you with a free Socketing from Larzuk, as well as a much welcomed shop discount on wares offered by the merchants. It is recommended to complete this, as without it, you will be paying nearly twice as much gold for the same items compared to Acts I-IV.
 * Completing the Rescue on Mount Arreat earns you the privilege of hiring Barbarians, and the necessary Runes for the Ancient's Pledge.
 * Completing the Prison of Ice rewards you with a Rare item exclusive to your class from Anya, custom made by Larzuk, as well as a Scroll that adds All Resistances +10 from Malah.
 * Completing the Betrayal of Harrogath allows you access to Personalizing an Item of your choice from Anya.