Immortal Eyes in Last Epoch are surprisingly difficult to find if you need to kill them for specific loot tied to a Prophecy objective. These enemies are a common target if you choose to join the Circle of Fortune, Last Epoch's faction that lets you find better items. It turns out, there's a bit of a hidden requirement to get credit for killing the right enemy type.
Immortal Eyes are undead enemies found in Necrotic-themed areas in Last Epoch. If you need to kill them to fulfill a Prophecy objective, you have to visit the specific areas they can spawn in, otherwise you'll never find them. There are also enemies who look identical but are named "Immortal Watchers" who won't count towards your progress, so be sure to check their names, too.
Several players report that they don't get credit for killing them or that they don't drop loot, so it's possible it might not work for you. Last Epoch's server issues could be the culprit. You can try restarting the game or skipping it for now if you follow these steps and still don't get credit.
The first step is to check your Prophecy and see if it asks you to find Immortal Eyes in normal zones or in a Monolith of Fate, Last Epoch's endgame activity. This will determine where you need to go to find them.
The second step is to visit one of the zones below and look for Immortal Eyes to kill. This may take a while if they don't spawn or if you encounter a bug where you don't get credit.
According to a fan-made Last Epoch wiki site, Tunklab, there are plenty of zones you can travel to on your map where Immortal Eyes spawn:
The Great CollegeImperial WelrynThe Risen LakeThe Felled WoodImperial ThetimaThe Imperial DreadnoughtThe Dreadnought's DeckThe Maj'Elka WaystationFor Monoliths, you can find them in these timelines:
Fall of the OutcastsBlood, Frost, and DeathReign of DragonsFall of the EmpireSpirits of FireBased on your Prophecy's objectives, make your way to one of those locations and search for the Immortal Eyes enemies. It's unclear if they're guaranteed to spawn in each area, so you might have to go to another map if they don't start to show up. When you do find some to kill, they should give you credit and the loot your Prophecy promised.