- Objective: Destroy Baal and his minions.
Trigger the sixth and final quest in Act V by defeating the barbarian Ancients on the Arreat Plateau. When you defeat one barbarian, he returns to statue form (now gold). Defeat all of them, and a new entry in your quest logbook appears under the sixth quest. Walk beyond the Ancients and open the passage into the Worldstone Keep, Level 1.
Enter the Worldstone Keep, Level 1 from the Arreat Plateau (you will probably need to town-portal back to Harrogath before you enter the Worldstone Keep). You must traverse three levels of the Worldstone Keep to the Throne of Destruction, where you encounter the expansion's final boss, Baal. There's a waypoint marker at the Worldstone Keep, Level 2. Make sure you activate this waypoint in case you die and need to return to the keep's depths.
- Recommended Level to Complete Quest VI
You gained a level upon defeating the barbarian Ancients. You're likely nearing level 40 by this point (approximately 35 to 37). Should you wish to attempt to level up, make sure you have visited Act V's optional dungeons: Abaddon, Pit of Acheron, Infernal Pit, and Icy Cellar. Proceed to the Worldstone Keep and the Throne of Destruction after exploring these areas.
Log Entry #1
Find Baal's Throne Room.
You'll find Baal's Throne Room at the bottom of the Worldstone Keep. Traverse three levels of the Worldstone Keep (beginning at the entrance off of the Arreat Plateau) and enter the Throne of Destruction from the Worldstone Keep, Level 3. Be sure to activate the waypoint in the Worldstone Keep, Level 2 or you could be in for some serious backtracking should you perish without a town portal in the Throne of Destruction.
When you reach the Throne of Destruction map, cross to the far side and locate Baal on his throne. You can't harm Baal just yet! Instead, he summons five sets of minions and unique monsters for you to battle through before you can get a shot at defeating him.
Log Entry #2
Kill Baal's Minions.
Reaching Baal in the Throne of Destruction triggers a new entry in your quest logbook. You must defeat Baal's minions (five groups, each with a unique monster) before you can battle Baal. The minions come in five consecutive waves. Once you defeat one wave, the next appears. Here are the five waves of minions and the unique monster with each (expect additional randomized properties on higher levels).
- Colenzo the Annihilator (demon fire enchanted; immune to fire) with warped shamans
- Achmel the Cursed (undead; immune to poison) with unravelers and death mages
- Bartuc the Bloody (demon lightning enchanted) with council members
- Ventor the Unholy (demon extra fast) with venom lords
- Lister the Tormentor (demon spectral hit) with minions of destruction
All of these minions and unique monsters appear at the foot of Baal's throne. Stay away from this area! If there's a single minion left from a set, lure him far away from Baal's throne before you kill him. It's easy to be surrounded by these powerful monsters if you hang around Baal's throne carelessly. Likewise, cast town portal away from Baal's throne toward the entrance to the Throne of Destruction so you are far away from the minions should you need to return to Harrogath and then reenter the map.
Log Entry #3
You've reached Lord of Destruction's final boss battle. Once you eliminate the final unique monster and set of minions, Baal exits his throne and moves into the Worldstone Chamber. Follow Baal through the opened portal. In the Worldstone Chamber, Baal begins on the narrow walkway above the Worldstone. Maneuver around the map and defeat the festering appendages holding you back from Baal himself.
Baal is the toughest beast you've faced thus far. He has several different spell attacks, including a close-range lightning attack, a ring of fire, and an arrowlike cold burst. All of these can be devastating, depending on your resistances. Baal also creates a double, which causes problems for you, since hitting the double does nothing to further your goal of defeating the lord of destruction. Make sure Baal's moniker "Demon" is centered under his name so you can distinguish the real Baal from the fake one.
There's no correct strategy for defeating Baal, but there are some important things to remember. Make sure you have a town portal up at all times so you can return to the Worldstone Chamber after a death or take a trip back to Harrogath to replenish health potions and town portal scrolls. Use some type of ranged attack or summoning to keep away from Baal's attacks or to distract Baal to attack something else besides you.
As an assassin, use your traps if you possess the necessary skills. A druid should use his pets, if you have chosen that specialization. Even a shape-shifting werebear or werewolf with ample hit points (use oak sage) and armor can withstand a close encounter with Baal. Be prepared with ample health potions and town portal scrolls for a quick exit back to Harrogath to regroup for another assault.
If you're playing as a sorceress, use mana shield to get close and cast static field to weaken Baal. Hide behind a pillar or stalagmite to blast Baal where he can't return fire. If you're playing as an amazon, summon a valkyrie to distract Baal's attacks and use guided arrows to damage Baal. As a paladin, position yourself behind a pillar or stalagmite and use blessed hammer attacks. Necromancers can use minions and bone spirits. Barbarians may have to battle toe-to-toe but can use whirlwind to spin quickly past, causing damage but moving away at a distance, or they can use leap attack as a pseudo range attack.
Completed from Tyrael
"I am impressed, mortal. You have overcome the greatest challenge this world has ever faced and defeated the last of the Prime Evils. However we are too late to save the Worldstone. Baal's destructive touch has corrupted it completely. Given enough time, the Worldstone's energies will drain away and the barriers between the worlds will shatter. The powers of hell will flood into this sanctuary and eradicate your people and everything you've labored to build. Therefore, I must destroy the corrupted Worldstone before the powers of hell take root. This act will change your world forever--with consequences even I cannot foresee. However it is the only way to ensure mankind's survival."
Baal drops several rare, unique, or magical items (better items on the higher difficulty levels), and you also unlock the concluding cutscene. Your character receives a new title depending on difficulty level and game mode. The new titles are:
- Standard, Normal Difficulty: Slayer
- Standard, Nightmare Difficulty: Champion
- Standard, Hell Difficulty: Patriarch (Matriarch for female characters)
- Hardcore, Normal Difficulty: Destroyer
- Hardcore, Nightmare Difficulty: Conqueror
- Hardcore, Hell Difficulty: Guardian