Cthulhu: The Cosmic Abyss is an adventure game based on Lovecraftian themes, where you have to try to stop Cthulhu from awakening. You’ll also have to solve many puzzles as you try to decipher what the Yith are trying to tell you. You’ll have to solve their riddles to unlock the full potential of the Star of Shamash.
For more information on the game, please visit its official Steam page.
Table of contents
The Last Door
After you take the Star of Shamash from the Citadel, you’ll be teleported to a new location, one made of Yith architecture.
There’s a pillar downstairs. It has a slot for the star. However, you’ll have to turn the star in such a way that the engraved side is opposite to the one that you’re currently facing.
Place the star on the pillar, and that will open the door ahead. Take the star back and proceed through the area. There’s a stele to your left. Interact with it, and you’ll decrypt the language.
There’s a stele at the end of the hallway. Check it out and go through the hallway. You’ll then eventually arrive at the Last Door. Put the star in the base of the Last Door, and it will extend outward, and stairs will appear on both sides.
Exploring The Area
As you step down the stairs, you’ll find the Last Door surrounded by pillars. These pillars are in the Yith language. Each of the pillars gives you a hint about something.
You can also obtain three different types of frequencies by inspecting some pillars. After that, if you look around, you’ll find several circular metal plates on the Last Door. These are the same ones that you encountered inside the temple.
If you look around, you’ll also find some metal cubes in the area. Each of the chambers here is locked behind a pyramid-shaped mechanism.
If you pull this mechanism out, it will turn back into a cube, and you’ve got no way to turn it back into a pyramid for now.
The Engravers
Go down the left pair of stairs. You’ll find a room locked behind a strange mechanism at the bottom. This is the only platform that won’t retract, even if you pull out the pyramid.
To unlock the door, you’ll have to use the sonar with ultrasonic stone sound. It can be obtained by interacting with the pillars above.
Once you go inside, you’ll find many engravers on both sides of the room. There’s also a pillar in the middle. There’s also a hole in the front of the pillar with the shape of a letter that can be found on the engravers.
Go to the engravers on the left side, and place the star on the bottom letter in the front column. After you’ve engraved it with the letter, push the engraved side of the pillar in the middle of the room.
Reconstruction: The Imprisonment
Here, you’ll hear the voice of a consciousness. It will tell you about the Elders and how they’re holding back Cthulhu.
If you look closely, you’ll see some silhouettes holding some stone tablets. Inspect each one of them.
After that, you have to make your way to the Memorial of Possibilities. Investigate the area and then approach the pillar in the middle. There’s also a slot here where you can put the star in.
Reconstruction: The Possibilities
After you put the star in the pillar, you’ll be teleported to a new area. Here, you have to inspect the tablets that are on the sides and on the table.
You’ll also find a sample for Pyrite, which can be analyzed to learn its frequency. The Pyrite frequency allows you to turn the mechanical cubes into Pyramids, and you’ll be able to access more chambers with it.
There’s also an incomplete star map here. You have to interact with it. You’ll need to gather some more clues to complete the star map.
Now that you can turn the cubes into pyramids, you can access the Memorial of Emergency. When you get there, you’ll find another pillar with a slot.
Reconstruction: The Emergency
In this Reconstruction, you’ll find several tablets displayed on the table. There’s also a fresco covered with symbols on the wall. These are the only things that you’ll need from here.
After that, you can leave the area by taking the star. Open the Vault. There will be a deduction attached to the incomplete star map. Connect it with the fresco you just investigated, and it will give you a list of symbols and names.
The Hidden Chamber
One of the chambers is blocked by overgrown sap. It won’t open even if you put a pyramid in front of it. You can only get there via teleportation. First, you’ll have to enter any Memorial Chamber.
There will be a base near the fresco. You have to put the star on the fresco in such a way that the Kelendhar symbol is facing you. It is the same symbol that you were pushing against the slots on those pillars to enter the Reconstructions.
After putting the star on the base, you have to look at it for a few seconds. The star will begin to glow and become awakened. If you take the star, you’ll be teleported to the hidden room below the hallway. You’ll also find the remains of a human here.
Furthermore, you’ll also find the pigment’s frequency. There’s also a chest here. The chest reacts to frequencies. You’ll have to combine the Infrasonic Stone and Hypersonic Stone frequencies to unlock the chest.
You’ll find many mechanical cubes here, with a stone tablet hidden underneath them. There are also many bases on each side of the room. You can place the star on any of them to teleport inside any chamber in the area.
This will allow you to visit the chamber that’s blocked by the sap. Here, you’ll find the Electrum frequency, which is something you wouldn’t already have if you did the Corruption Path in the Temple.
You’ll have to visit every chamber again, now that you have the pigment frequency. After arriving in the chambers, use the pigment frequency to unlock the hidden text and images in the area.
Furthermore, you’ll also have to get on top of the Last Door and use the pigment frequency, as many of the pillars on the door will have their text reconstructed after the pigment frequency has been used near them.
Corruption And Non-Corruption Paths
Like most other chapters, you can take either the Corruption path, which will increase the corruption of your brain, or pick the Non-Corruption path, which will decrease the corruption.
For the Corruption path, you have to do nothing. If you open the Last Door without doing anything extra, your corruption will increase as the sap will come through after the door opens.
For the Non-Corruption path, you’ll have to use the Electrum frequency on the mechanical cubes and turn them into spheres.
After that, you’ll have to place those spheres on the multiple circular metal plates that are present on the Last Door’s platform.
Engraving The Star
You have to use the Prayer Pillars for hints and the pigment-scanned pictures of frescos to uncover the true symbols behind the names of the five Elders.
Go to the chamber on the bottom left with the engravers. You’ll have to use these engravings in the following order:
Imh’tar should be on top. This is the side that will be facing the sky. Vulghred’s symbol goes behind Imh’tar, to the south of it. Yhom’s symbol goes to the front side of Imh’tar, opposite of Vulghred. Thultris’s symbol goes opposite to Imh’tar, on the bottom side of the star. Azdryggh goes to the right, while Mexhart goes to the left side of the star, opposite each other.
If the star starts to glow, you can then head to the main platform and put the star there. This will be a short cutscene, and you can then proceed to Chapter 7, where you’ll get to the ending.
This concludes the walkthrough for Chapter 6 of Cthulhu: The Cosmic Abyss.
If you’re looking for more walkthroughs, please visit the game’s main hub here. You may also like the following walkthroughs:
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Fahad Suleman is an avid fan of fighting games who spends most of his time writing walkthroughs and reviews for cozy indie titles or mashing around in Tekken. If he’s not writing or playing any games, you’ll often find him watching historical videos on YouTube for hours.
