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Overview
Gate to the Otherworld is the 56th main quest in Crimson Desert and the signature quest of Chapter 4. It combines environmental puzzles with a unique aerial boss battle against Tenebrum, a spectral entity summoned by Octavius from the Abyss. The quest takes place in and around the central plaza of Scholastone Institute and is divided into four phases: solving the underground lock device, inserting batteries into pillars, extracting an unstable core, and fighting Tenebrum in the air.

You will need the Blinding Flash and Force Palm abilities to complete this quest. Both are used extensively during the boss encounter, while Force Palm is also required for the battery insertion phase.
Quest Details
Detail | Info |
|---|---|
Quest Number | 56 |
Chapter | 4: The Price of Knowledge |
Sub-Chapter | |
Region | |
Prerequisite | |
Required Abilities | |
Rewards |
Objectives
Remove the unstable core
Defeat Tenebrum
Phase 1: Underground Lock Device
To begin Octavius's experiment, navigate to the northeast corner of the plaza where lanterns mark a descending path. Float down over the edge of the courtyard and glide to the level below, then enter through an open window to reach the underground chamber. For a detailed guide on this puzzle, see Activate the Lock Device Switch Underground.
Puzzle Mechanics
Inside the underground chamber you will find a hatch mounted on the wall with nine strongbox components arranged in a 3x3 grid. Pressing any one tile toggles it along with nearby tiles in an L-shaped pattern, so you cannot simply press them one at a time. The goal is to illuminate all nine tiles simultaneously. Use D-Pad Left and Right to select which tile to press.
Button Solutions
Because each press affects multiple tiles in an L-shaped pattern, there are several valid sequences that solve the puzzle. If you press the wrong button and the grid resets, just start over. Here are two confirmed solutions:
Solution 1: Middle, Top-left, Bottom-right, Top-right, Bottom-left.

Solution 2: Top-right, Bottom-left, Middle, Bottom-right, Top-left.
When all nine tiles glow simultaneously, the puzzle is solved. Pull the switch on the wall to activate the mechanism, which opens the ceiling above and grants access back to the plaza.
Phase 2: Battery Insertion
Climb back up to the circular plaza. Four floating electric cubes (the batteries) surround the central device. Each cube appears as an orange marker on the minimap, making them easy to locate. For a detailed guide, see Insert Batteries to Activate the Device.
For each of the four batteries:
Use Axiom Force (hold L3/LS) to grab the floating cube.
Guide it toward the corresponding pillar slot using R2/RT. Orient the cube so the side with the four lights faces you.
Position the cube directly in front of the pillar opening. The cubes will not slot into place with Axiom Force alone.
Release the cube, then immediately use Force Palm (R3) to punch the battery into its slot.
After all four batteries lock into place, each pillar emits a beam of energy aimed at the central sphere. The device powers up and a cutscene plays, signaling the start of the next phase.
Phase 3: Remove the Unstable Core
With the four energy beams converging on the central sphere, aim at the glowing blue orb using L3/LS. Activate Axiom Force by holding L2/LT and push the right stick upward for several seconds to extract the sphere. Keep holding until the extraction animation completes. Releasing early will reset your progress, so maintain pressure on the stick throughout.
Once removed, the unstable core triggers a dramatic reaction that tears open a rift in the plaza. Octavius's experiment has succeeded, but the consequences are immediate: a shadowy creature called Tenebrum emerges from the rift.
Phase 4: Boss Fight, Tenebrum
Tenebrum is an aerial enemy summoned from the otherworld. It takes the form of a plume of dark smoke that dances around the arena, moving unpredictably at high speed above the plaza. This fight uses completely different mechanics from any previous boss encounter in the game, relying on gliding, wind currents, and mid-air Force Palm strikes. It functions more as a puzzle than a traditional combat encounter. For a detailed strategy, see How to Defeat Tenebrum.
Tenebrum's Attacks
Attack | Description |
|---|---|
Dark Strike | Close-range punch. Cannot be blocked. Dodge sideways to avoid it. |
Tenebrum launches dark projectiles that deal damage and can knock you out of the air. Weave between them while gliding or take cover behind pillars. | |
Dark Whip | Ranged lash attack and Tenebrum's most frequent move. Stay mobile and change direction to avoid the sweep. |
Dark Whirlwind | Area-of-effect spin that creates dark whips around itself. Retreat behind pillars when you see Tenebrum winding up this attack. |
Tenebrum moves to the center of the arena and begins charging an explosion. This is your main attack window. Fly in and hit it with Force Palm before the shockwave detonates. If the explosion goes off, expect significant damage. | |
Relocate | Tenebrum teleports to a new position. Watch for shadow trails to track where it moves. |
Fight Strategy
Reveal the weak spot. Hold L1 + R1 to activate Blinding Flash. Press R1 to target Tenebrum and expose a square weak spot on its body. You only need to do this once at the start of the fight.
Take flight. Move to the center of the plaza where the floor has been destroyed. Double-press Square/X to jump and activate your wings. Wind currents throughout the arena launch you upward toward Tenebrum. The winds allow you to move around freely as long as you have stamina.
Attack with Force Palm. Glide toward the shadowy creature and press R3 for a mid-air Force Palm strike. The best window to deal damage is when Tenebrum pauses in the center of the arena to charge its shockwave attack. These stationary moments are the safest openings.
Dodge projectiles. Tenebrum fires dark projectiles that deal damage and knock you down. Avoid them while airborne by changing direction, or use stone pillars around the arena edges as cover.
Recharge Spirit. When your Spirit gauge depletes, land behind one of the stone pillars for cover and press L3 + R3 simultaneously to regenerate. Flying consumes no stamina in this arena, so Spirit is your only resource to manage.
Heal. Use D-Pad Right for food items when health gets low. You can heal while behind pillar cover.
Three successful Force Palm strikes on Tenebrum's weak spot are enough to end the fight. After the third hit, a cutscene plays and the boss is defeated. If you happen to run out of stamina and fall to the level below during the fight, you will respawn upstairs and Tenebrum's missing health will remain depleted, so you do not lose progress.
Once defeated, pick up the Abyss Artifact that spawns where Octavius was standing to complete the quest. You will also receive a key for the Spire of the Stars, which is your next destination.

Aftermath and Next Steps
Defeating Tenebrum completes the Gate to the Otherworld quest and unlocks the path forward in Chapter 4. Two follow-up quests continue the storyline at Scholastone Institute.
Spire of the Stars
The next quest, Spire of the Stars, requires you to collect three Engraved Stones and solve a symbol-based elevator puzzle. Each stone is obtained by using Force Palm on wall buttons hidden in side corridors: one stone in the left corridor and two in the right corridor. Once all three stones are inserted into the central mechanism, you must position four symbols at the correct heights on vertical bars by climbing onto each symbol's plate and letting it descend.
Spire Symbol Positions
The murals on the left and right walls indicate the correct arrangement. From left to right, the symbols and their positions are:
Symbol | Position (Left to Right) | Vertical Rung |
|---|---|---|
1st (leftmost) | Topmost (already in place) | |
Circle | 2nd | Second from top |
Triangle | 3rd | Third from top |
Square | 4th (rightmost) | Bottommost |
To lower a symbol to the correct rung, climb the wall next to it, grab the handlebar, and hang until the plate descends one position. Release when it reaches the target height. Once all four symbols are correctly placed, stand on the central pillar. The symbols glow blue, the elevator activates, and a platform carries you to the top of the spire.
Obsession and Madness
After reaching the top of the Spire, the quest Obsession and Madness begins. Your first task is to establish an Abyss Nexus fast-travel point near the entrance to the Abyss. To reach the main platform, climb the tall pillar in the center of the area, then glide across to the large floating structure. Activate the ground switch by performing a jumping Force Palm near the circular arch on the platform. This quest ultimately reveals the identity of the person responsible for the rift and for what happened to Octavius.
Tips
The underground lock device has multiple valid button orders. If you press the wrong button, the sequence resets. Just start over from the beginning.
Each tile press in the puzzle creates an L-shaped activation pattern. Knowing this helps if you want to work out the solution yourself rather than following a guide.
For the battery insertion, orient each cube so its four-light side faces you before releasing. The Force Palm punch is the critical step; Axiom Force alone will not slot the cube into place.
Each cube corresponds to a specific pillar. Check the minimap for the closest orange marker to avoid dragging cubes across the entire plaza.
The Tenebrum fight is more confusing than difficult. Once you understand the flight mechanics and Blinding Flash, it goes quickly.
Stock up on healing food before starting this quest. The boss fight can drain your health if you get hit by projectiles.
During the Tenebrum fight, use the wind currents scattered across the arena floor to gain altitude quickly. You do not need to rely on jumping from pillars alone.
If you fall to the ground during the boss fight, do not worry. You respawn upstairs and Tenebrum's missing health stays depleted, so no progress is lost.
The best time to attack Tenebrum is when it drifts to the center of the arena to charge its shockwave. Fly in and use Force Palm before the explosion goes off.
Related Quests
Previous quest: On the Right Path
Next quest: Spire of the Stars
Objective guides: Activate the Lock Device Switch Underground, Insert Batteries to Activate the Device, How to Defeat Tenebrum