Diablo 1 Walkthrough -> Archbishop Lazarus
On the rack itself, you'll find the Lazarus Rod, which will initiate this mandatory quest. You must take the rod to Deckard Cain the Elder, who will tell you its meaning with horror.
It turns out the elder had long suspected that Lazarus was the indirect cause of the misfortunes plaguing the city, but now there's concrete evidence. Kane will reveal that Lazarus kidnapped Leoric's only heir, Prince Albrecht, apparently to bring back to life his dark master, the Lord of Terror, Diablo. And they needed the boy for a dark ritual.
After this, a Red Portal will appear above the pentagram, leading to Lazarus' Secret Lair. This is where our enemy is hiding, but reaching him won't be easy. First, you'll need to defeat two groups of enemies—succubi and mages—who await you in the rooms to the right and left of the main corridor.
It will take you to the final room, where the traitor Lazarus awaits you behind a sacrificial altar. He's not alone: next to him are two unique succubi demonesses, and just below is another group of succubi. All the monsters are ranged, so be prepared for a tough fight.
The following spells can help you: Golem, Stone Curse, and Apocalypse. The most effective tactic, in my opinion, is to first deal with the group of succubi at the bottom of the room to give yourself room to maneuver. If you find an Apocalypse scroll, run up to the succubi and cast it on them.
On Normal mode, one scroll is enough to kill these witches. The remaining succubi and Lazarus can be distracted by Golem, slowed by Stone Curse, and finished off. After defeating Lazarus, return to the beginning of the level, go through the portal again, and tell Kane everything. He'll complete the quest and give you the final task in the game.
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