The Mound: Omen of Cthulhu Guide | How to Unlock the Mound
Here's a guide on how to unlock the Mound and enter the Underworld in The Mound: Omen of Cthulhu.
Game Guide by Jubair Baky on Jul 30, 2026
The red barrier at the Mound entrance cannot be opened simply by reaching the location. In The Mound: Omen of Cthulhu, you must first complete a chain of Fort's Logbook and Mysterious Artifact expeditions, recover five Tulu metal cylinders, and then launch the expedition that takes you inside.
Unlock the Mysterious Artifact Expeditions
Begin by completing the expedition that asks you to recover the Fort's Logbook for the relevant area. Returning the logbook unlocks a new set of expeditions called Mysterious Artifact. These contracts require you to bring a Tulu metal cylinder back to the Captain.

Recover All Five Tulu Metal Cylinders
There are five-cylinder contracts to complete. During each expedition, listen for the artifact's distinctive sound and look for green mist marking its position. The exact spawn can vary within the contract area, so use both cues while searching.

Picking up a cylinder immediately triggers a Blood Moon. Carry it back to the wagon and secure it on the rear storage area. Loading it onto the wagon ends that forced Blood Moon, allowing you to return to the extraction point with the artifact.
Activate the Five Statues
Each successfully returned cylinder lights one of the five statues beside the Mound entrance. The red barrier remains active until every statue has been illuminated, so finding the entrance early does not let you bypass the contract progression.
Start The Mound: Explore the Underworld
After returning all five cylinders, speak to the Captain and check the expedition list. The Mound: Explore the Underworld will now be available. Starting it transports you directly into the Mound instead of sending you through the red barrier from a normal expedition.

The wagon cannot accompany you into the Mound. Fill your inventory with healing supplies and any essential equipment before starting the expedition.
After recovering all five Tulu metal cylinders, select The Mound: Explore the Underworld to enter the Mound.
FAQ
Q. How many Tulu metal cylinders are required to unlock the Mound?
A. You must return five Tulu metal cylinders, with each one lighting a statue near the entrance.
Q. Why is the red barrier still blocking the Mound entrance?
A. Reaching the entrance is not enough. The barrier remains until you complete all five Mysterious Artifact cylinder contracts.
Also, check our The Mound: Omen of Cthulhu Review and other guides below:
- The Mound: Omen of Cthulhu Beginner’s Guide | Tips You Need to Know
- The Mound: Omen of Cthulhu Guide | How to Complete the Portal Mission
- The Mound: Omen of Cthulhu Guide | How to Use the Medallion to Find Loot
- The Mound: Omen of Cthulhu Guide | How to Complete the Remedy Run
- The Mound: Omen of Cthulhu Guide | How to Find Logbooks Quickly
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- The Mound: Omen of Cthulhu Guide | How Extra Knives and Rank Rewards Work
- The Mound: Omen of Cthulhu Guide | How to Complete a Portal Contract
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- The Mound: Omen of Cthulhu Guide | How Patron Saints System Work
- The Mound: Omen of Cthulhu Guide | How Isolation Works
- The Mound: Omen of Cthulhu Guide | How to Avoid Blood Moons
- The Mound: Omen of Cthulhu Guide | Sanity System Explained
- The Mound: Omen of Cthulhu Guide | How the Block Mechanic Works
- The Mound: Omen of Cthulhu Guide | How to Stop Enemy Revives Using the Root Mechanic
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