In Diablo 2 Resurrected, in order to complete the Pandemonium Event, players first need to collect the three main keys, the Key of Terror, the Key of Hate, and the Key of Destruction, on Hell difficulty. After collecting all the keys, the player needs to go to Harrogath. Place the player's keys in the Horadric Cube in turn for conversion.

If the player has collected all the keys, the player can open the red portal to the three locations Matron's Den, Forgotten Sands and The Furnace of Pain. The opening order of these Diablo 2 Resurrected Runes places is completely random. Players will find Lilith in Matron's Den. Her poison spray is particularly deadly. After defeating Lilith, the player can collect Diablo's Horn from her.

Uber Duriel is equipped with a similar Holy Freeze Aura and other attacks. Players will get Baal's Eyes from Forgotten Sands. Uber Izual is a more dangerous version of the super-unique quest monster Izual, found in the Plains of Despair in Act IV. Mephisto's Brain is a drop that players need. Players will encounter Uber Izual in Furnace of Pain.

Players need to place Diablo's horn, Mephisto's brain, and Baal's eyes in the Horadric Cube to open the red portal to the Uber Tristram. Here, players will encounter Uber Mephisto, Uber Baal, and Pandemonium Diablo. Their abilities, defense mechanics, attack effects, and health have all been significantly improved, making them more difficult to deal with than usual.

Players also have to deal with the minions they summon. When completing the Diablo 2 Pandemonium Event, the main reward that players will be able to earn is the Hellfire Torch, a one-of-a-kind special large amulet that can only be obtained by completing the Diablo 2 Pandemonium Event. Along the way, players can also purchase unique Diablo 2 Resurrected Items from  MMOWTS to boost their power.