The City of the Dead is very dangerous, but it also offers great rewards if you know where to look. This Path of Exile guide for the Lantern of Arimor in Necropolis will help you get the rewards on offer here.
Maximize Rewards with the Lantern of Arimor – Poe 3.24 Necropolis League Mechanic Walkthrough
In Act 1 of Necropolis you will get the Lantern of Arimor from the Undertaker Arimor. This NPC carries the corpses and drops them in the Necropolis, and once you meet him he will give you the Lantern of Arimor. You can read about Balabus Arimor during a raid. He is a mystic who believes he can achieve immortality through ritual sacrifice.
This item can be used to view and change all modifiers in the battle zones in Necropolis if necessary. Modifiers include finding rare items, weapons, or NPCs, such as Nameless Seer.
Before entering each zone of Necropolis, the Lantern of Arimor automatically gives all monsters in the zone and any Haunted modifiers those monsters are carrying. The Haunted modifiers give certain monsters increased stats, but sometimes there are Devoted modifiers instead of Haunted that work to the player's advantage. You'll need to kill a lot of high-tier monsters to earn those, though.