Tristram (Über)
The Pandemonium Event culminates in a single portal that drops all three Prime Evils into the same arena. Before any of that happens, you need the three organs. Defeat Lilith in the Forgotten Sands, Über Izual in the Furnace of Pain, and Über Duriel in the Matron's Den, then combine Diablo's Horn, Baal's Eye, and Mephisto's Brain in the Horadric Cube while in Harrogath on Hell difficulty. The portal opens in town.
Preparation determines whether this run is manageable or a wipe. Two things matter most:
Overcap Lightning and Cold Resistance to 300%. Über Mephisto's Conviction Aura cuts Resistances by 125% — without the buffer, you will be running dangerously low on both. Fire and Poison are not priority targets for overcapping.
Bring sustain. Dracul's Grasp is the standard solution for melee builds — the Life Tap proc keeps you alive through the heaviest hits. Until the first proc fires, rely on Full Rejuvenation Potions. A Wand of Life Tap on weapon swap, shopped from vendors in Nightmare Act 1 from Level 30 onward, lets you pre-apply Life Tap before the gloves proc.
Clear the zone first. Oblivion Knights and Hell Temptresses near Lilith and Izual spawn with Amplify Damage. Getting cursed while already fighting the Ubers can instantly kill a budget build. Sweep the surrounding area before pulling any of the three.
All three Ubers spawn at the center of Tristram with Extra Fast, Magic Resistant, and a single elemental Immunity each. Engaging all three at once is rarely viable — the standard approach is to isolate each one.
Enter the portal and go left. Use every buff available, then advance slowly toward the center. Über Mephisto will break off first — he is the highest-threat target. His Conviction Aura amplifies his spells, Lightning Enchant adds Charged Bolts on top, and he continuously summons Skeleton minions across all three types. He is Immune to Lightning. Pull him to the top-left corner and kill him before any minions stack to dangerous numbers.
With Mephisto down, loop around to the bottom-right river. Move toward the middle house until Über Baal locks onto you. He will Teleport in — let him come to you and fight him at the riverbank. His direct damage output is low, but his Chilling Armor sharply reduces Hit Chance for attack builds, his Life pool is the largest of the three, and his Specters and Dark Lords are both Physical Immune. Specters also carry Mana Burn, which can stall mana-dependent builds if they accumulate.
Über Diablo is last and poses the least threat individually. He is Immune to Fire and notably frailer than his brothers. His Armageddon-type spell deals damage over time and his Pit Lords are immune to everything except Physical — let them accumulate and they outpace Diablo himself in danger.
Killing all three Über Prime Evils drops a Hellfire Torch — a Large Charm with class-specific bonuses and powerful base stats. It is one of the most universally sought items in the game and the entire purpose of running this event.