Eldric is an astronomer specializing in celestial phenomena and omens. He noticed the Eye of Cthulhu stirring in the night skies and wants the player’s help to prevent impending danger.
Eldric has robes adorned with star patterns, carrying a staff topped with a moon crystal.
Eldric can be found in the unbuilt Observatory in Ravencrest after the King Slime has been defeated.
Eldric notices the player's involvement with defeating King Slime and offers to share his concerns about the Eye of Cthulhu. This quest is only available after the King Slime questline is completed.
Starting: Speak to Eldric in Ravencrest
Eldric greets you, and notes his unbuilt observatory. Then, however, Eldric mentions that something's messing with the stars - a great eye.
Eldric sends the player to collect 5 Lunar Shards, rare fragments found on wandering enemies at night, symbolizing the growing power of the Eye. Additionally, he asks you to get a bizarre concoction that Garrick carries called the Lunar Liquid. From these two, he can make a potion that'll send you right to the Eye's hideaway. He'll be building his observatory while you work.
---
Next: Talk to Garrick for the Lunar Liquid
Garrick hands you a “Lunar Liquid". He says that he had been tasked with keeping it for just this situation…and that Eldric seems to undersell the Eye's strength.
Next: Return to Eldric with 5 Lunar Shards
Eldric thanks you for the shards.
If you haven't yet talked to Garrick and obtained the Lunar Liquid, he'll tell you to talk to Garrick to move along. After doing so, returning to Eldric will continue the quest.
If you have already talked to Garrick, he'll give you the Lunar Concoction, a potion that, when thrown on the ground, will summon a portal to the Eye of Cthulhu's domain. He, again, continues building his observatory while you work.
---
Next: Kill the Eye of Cthulhu
Upon throwing the Concoction to the ground, swirling stars crash down where the bottle was broken, and forms a portal that can be entered to travel to the Eye of Cthulhu domain.
If you fail to kill the Eye and return to the overworld, Garrick can be given 5 Lunar Shards to create another Lunar Liquid, and then Eldric can be given an additional 5 Lunar Shards to create another Lunar Concoction, until the boss is defeated.
Next: Talk to Eldric
Eldric thanks you, stating that the skies are safe. The observatory should be fully built by the time you come back, and to come back if desired. The quest ends at this point.
“The world's tumultuous, isn't it?”
“Stay calm, even if the land around isn't.”
“Would you ever enjoy a tea? I certainly would.”
“Magic is but one solution. Practicality is another. Bear this in mind.”
Upon starting:
“Hello, traveler. You've stumbled across my soon-to-be observatory…soon. However, I have noticed something in the sky as of late. The last time it passed by was when I was a child. A great eye looks down upon us, and is causing some issues in the stars. We have no better a warrior to stop the Eye; may you take him? We'll just need some Lunar Shards from Demon Eyes and Zombies. Talk to Garrick, he knows the pther part of the concoction.”
Selecting ‘Create Concoction’ without needed Lunar Shards / Failing the Eye of Cthulhu fight:
“Hm, didn't succeed with the Eye? Ah. Well, I believe Garrick can get you more of the Lunar Liquid, and then get me five more Lunar Shards and we'll be on our way.”
Handing in Lunar Shards:
“Thank you. Here's the concoction. Throw this upon the ground and it'll open a portal - temporary as it is - to the Eye's domain. You will have to repeat these steps if the portal is to close, so be sure you succeed. I will continue to build my observatory while you battle. Best of luck.”
After defeating the Eye:
“Just as I thought. The Eye returns to…wherever it happens to hide. Regrow? Whatever. I'm able to relax now. Hopefully you'll see this observatory up and running soon. Stop by, if you'd like.”