How to Activate the Lock Device Switch in Crimson Desert

In Crimson Desert, Chapter 4’s main quest, “Forbidden Knowledge,” Kliff secretly infiltrates the Scholastone Institute in Hernand while tracking Alustin. His investigation leads him into Octavius’s dangerous Abyss experiment, culminating in a battle with the Tenebrum boss. After conquering the Spire of the Stars, Kliff uncovers a stronger link to the Abyss, which ultimately sends him back to Howling Hill and concludes the chapter.

In Crimson Desert, the Forbidden Knowledge questline consists of seven smaller quests that you must finish one after another.

The Words of Alustin
Scholastone
On the Right Path
Gate to the Otherworld
Spire of the Stars
Obsession and Madness
Casted Shadow

The Words of Alustin Walkthrough

The Forbidden Knowledge quest starts in Hernand. While walking around the city, you’ll unexpectedly meet a messenger, and shortly after, you’ll get a letter from Alustin. Receiving Alustin’s Letter is what officially begins the quest.

If the messenger doesn’t appear, try walking around the area and then reloading the game or leaving and re-entering the zone. This should make them appear.

After you receive the letter, open and read it to find out where to go next. The letter will direct you to Scholastone, a private school located in the cold, western part of Hernand, close to Fort Perwin.

Scholastone Walkthrough

You’ll need a disguise to get into Scholastone. Start by going to the contact near the fence, arranged through Alustin, and enter the building close to the town square. Once inside, Darroch will give you the Scholastone Uniform. You must wear this uniform to get past the magical barrier and reach the hidden cave entrance to the institute.

Continue west towards the mountains, where it gets much colder. You’ll find your stamina doesn’t recover as quickly because of the freezing temperatures.

When facing freezing temperatures, wearing gear with Ice Resistance is beneficial. Combining this with stamina-boosting food or drinks, such as beer, can also help.

You’ll eventually find a hidden cave sealed by an energy barrier. To get through, put on the Scholastone Uniform. Inside, you’ll discover a new ability called Focus Force Palm, which allows you to activate glowing energy sources and unlock new paths.

Once you’ve triggered the device, a Troll will show you the way to the institute. From there, you have two choices: you can climb straight up, or take the winding path around the mountain until you see Scholastone.

On the Right Path Walkthrough

After you reach the Scholastone Institute, your next goal is to find Dean Grundir. He’s standing on a bridge just inside the main entrance. Because you’re wearing the uniform, you can follow him around without drawing attention. He’ll eventually introduce you to Octavius, a key character for progressing in the Forbidden Knowledge quest.

Once you’ve completed the initial steps, you’ll need to wait about one full day within the game before you can proceed. After that day has passed, speak with Octavius to begin the experiment.

Gate to the Otherworld Walkthrough

To begin Octavius’s experiment, you’ll first need to solve a puzzle located under the Scholastone plaza. You can reach the puzzle area by either taking the stairs down from where Octavius is standing, or by jumping off the ledge and gliding to the lower level.

Inside, you’ll discover a puzzle with several tiles that must all be pressed at the same time to unlock it. Pressing one tile changes others, meaning the order you press them in is crucial. The solution is:

Press the top left button
Activate the bottom right button.
Hit the top right button.
Press the bottom left button.
Press the central button to complete the sequence.

When everything is put together properly, each piece will securely lock, the structure will become stable, and the dome will open.

Now that you’ve solved the puzzle, you need to turn on the device. Do this by placing four energy cubes into the pillars above Octavius. Use Axiom Force to lift each cube and line it up with its matching slot. Once it’s aligned, switch to Force Palm and push the cube into the socket to lock it in place.

Once all four triggers are activated, Octavius’s experiment begins, but quickly malfunctions. The unstable core then becomes the primary danger. You need to use Axiom Force to secure the core from the center of the structure, all while dodging the hazards of the collapsing system. Successfully doing so will initiate the battle with the Tenebrum boss.

Defeat Tenebrum

Tenebrum is a floating enemy that can’t be harmed by regular attacks. To defeat it, you need to use the rising air currents to float up and strike it with Force Palm while in the air. Each hit does a lot of damage, so just a few well-aimed attacks will do the trick. Be careful, though – Tenebrum sends out bursts of wind and shadow projectiles, so hide behind the pillars and time your glides carefully.

After three solid hits, Tenebrum is defeated, and you get a Key to the Spire of the Stars.

Spire of the Stars Walkthrough

Your next stop is the Spire of the Stars, found at the top of the mountain above Scholastone. The path is covered in ice, which drains your stamina faster, so stay warm with special gear or by eating food that provides buffs. An ice-resistant cloak from the institute shop would be very helpful.

Head up the stairs, following the path through the caves and snow, until you find the entrance. Then, use the core you found to unlock the spire’s door.

Spire of the Stars Puzzle

To begin activating the Spire of the Stars, solve the puzzle at the entrance of the main chamber. First, use Force Palm on the three walls with glowing yellow panels. This will flip them over, revealing hidden stones that are essential for the activation mechanism.

Place the stones into the empty spaces on the central wall, next to the existing symbol. When all the stones are in place, the symbols will align, and the elevator will start, lifting the platforms above each symbol.

Now, climb up and lower the raised symbols into their slots by holding onto them. It’s a puzzle focused on getting everything lined up correctly. The order should be:

Left symbol goes in the top slot.
Middle left symbol goes in the second slot from the top.
Right symbol goes in the second slot from the bottom.
Middle right symbol goes in the bottom slot.

If you accidentally place something too far, you can use the Force Palm ability at its base to quickly reposition it and try again.

If everything is set up properly, the elevator will start and take you to the next floor. Then, keep going up the stairs until you find the Abyss Gate.

Obsession and Madness Walkthrough

In the Abyss level, you’ll start on floating platforms that are linked by huge, magnetic pillars. You can use the Axiom Force to pull your platform across gaps to these pillars. The best way to progress is to carefully move from pillar to pillar, beginning with the central structure.

To progress, you’ll constantly need to jump between different platforms and power up new structures. This will eventually lead you to an area you can climb, taking you to a higher island.

Up above, you’ll find a pressure plate that lights up when touched. If you activate it using Force Palm, it starts a big cutscene revealing a mysterious character and immediately takes you back to Scholastone, ending the Abyss section.

Casted Shadow Walkthrough

Once you escape the Abyss, you’ll find yourself back at Scholastone. Dean Grundir will talk to you about what happened, and after that, you’re free to go.

Your ultimate goal is to return to Howling Hill and rejoin the Greymanes. Once you’re back at camp and inside your tent, the Forbidden Knowledge quest will be finished, and Chapter 5 will start.

2026-05-05 14:07