Diablo 2 Walkthrough: Act 4, Pandemonium Fortress to Diablo

Part 4 of our Diablo 2 walkthrough covers Act 4, the shortest act in the game. You start at the Pandemonium Fortress, walk down through Hell itself and end by killing Diablo in the Chaos Sanctuary. There are only three quests, but the final fight is a big step up.

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The whole walkthrough

Quests in Act 4

1. The Fallen Angel
2. Hell's Forge
3. Terror's End

Only Terror's End is required, but you walk past the other two on the way, and both are worth doing.

The Pandemonium Fortress

This small town has everything you need: Tyrael gives the quests, Deckard Cain identifies items, Jamella sells potions and magic gear and Halbu sells and repairs weapons and armor. There is no mercenary for hire here, so your current one comes with you. Restock potions before you leave: the fights in this act come fast.

The route through Act 4

The act is a straight line: Outer Steppes, Plains of Despair, City of the Damned, River of Flame and the Chaos Sanctuary. Act 4 has only three waypoints, and you want all of them:

• Pandemonium Fortress (town)
• City of the Damned
• River of Flame (the Hellforge, and your start point for Diablo)

1. The Fallen Angel (Izual)

Tyrael asks you to free the trapped soul of the angel Izual.

1. Leave town into the Outer Steppes and continue to the Plains of Despair.
2. Izual walks around somewhere on the Plains. He is a big, fast melee demon who hits hard and also uses cold attacks.
3. Fight him in the open so you have space to back off and drink potions. Let your mercenary take some of the hits.
4. After he dies, return to Tyrael.

Reward: 2 skill points. This is the biggest skill point reward in the game, so always do it.

2. Hell's Forge (Mephisto's Soulstone)

Talk to Deckard Cain. You need Mephisto's Soulstone, which Mephisto dropped in Act 3. If you didn't pick it up, Cain gives you one.

1. Go through the City of the Damned to the River of Flame.
2. Find the Hellforge. It is guarded by Hephasto the Armorer, a tough unique demon.
3. Kill Hephasto. He drops the Hellforge Hammer.
4. Click the forge to place the Soulstone on it.
5. Equip the hammer and hit the Soulstone until it shatters. It takes a few swings.

Reward: a pile of gems of different quality, plus a random rune in the expansion (which D2R includes). Worth doing for the gems alone. Then switch back to your normal weapon.

3. Terror's End (Diablo)

From the River of Flame, follow the path to the Chaos Sanctuary. It is a big star-shaped hall full of strong demons. In the middle is a pentagram, and around it are five seals.

Opening the seals

Each seal is a glowing object you click. Opening certain seals spawns a seal boss with a pack of demons:

• Grand Vizier of Chaos: a unique Storm Caster who throws fire and lightning.
• Lord De Seis: a unique Oblivion Knight who casts curses and bone spells.
• Infector of Souls: a unique Venom Lord. He is fast and hits very hard. Most deaths in this act happen here, so be careful.

1. Clear the entrance hall first so you have a safe place to retreat.
2. Open seals one area at a time. Kill each seal boss and its pack before moving on.
3. Cast a Town Portal near the entrance before you start. If things go wrong, use it.
4. When all five seals are open and the three seal bosses are dead, Diablo appears in the middle of the pentagram.

What Diablo does

• Red Lightning Hose: a stream of lightning he fires straight at you. It is his most dangerous attack. Step to the side to break the line.
• Fire attacks: a ring of fire around him and a firestorm that runs along the ground.
• Bone Prison: he can trap you in a cage of bone. Break out or wait it out, but don't panic.
• A strong melee attack when you stand next to him.

How to beat him

1. Get your fire and lightning resistance as high as you can before the fight. These two matter most.
2. Bring a full belt plus extra potions. Rejuvenation Potions are worth saving for this.
3. Never stand still in a straight line from him. Move sideways, not straight back, when he starts the lightning.
4. Diablo stays in the central area, so you can step back into a side hall to heal or open a portal.
5. Most players kill him on Normal somewhere in the high 20s to low 30s.

When Diablo dies, Terror's End completes. Talk to Tyrael: he opens a portal to Harrogath, the start of Act 5.

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For the full lore of the Prime Evils, The Book of Cain is a great read between runs.

Tips for this part

• Act 4 monsters hit harder than anything before. If you were barely surviving in Act 3, gain a level or two in the City of the Damned first.
• Upgrade your mercenary's gear. Check Halbu's and Jamella's stock, it can beat what you have found.
• Keep the River of Flame waypoint: it is the quickest way back to the Chaos Sanctuary if you die.
• The Chaos Sanctuary is dark and crowded. Don't rush into packs you can't see yet.

My take

Act 4 is short, but I think it has the best atmosphere in the whole game, walking down into Hell still feels great. The Infector of Souls killed me more times than Diablo himself ever did. The 2 skill points from Izual are a nice gift right before the final fight. Which seal boss gave you the most trouble?

FAQ

How long is Act 4 in Diablo 2?

It is the shortest act. Most players finish it in one to two hours on Normal.

What level should I be for Diablo?

Around the high 20s to early 30s on Normal is common. Good fire and lightning resistance matter more than a couple of extra levels.

Why won't Diablo spawn?

You have to open all five seals and kill all three seal bosses: the Grand Vizier of Chaos, Lord De Seis and the Infector of Souls. If one is still alive, Diablo won't appear.

Is The Fallen Angel quest worth doing?

Yes. It gives 2 skill points on each difficulty, the biggest skill point reward of any quest.

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