Destiny 2 Season of the Haunted: Duality Dungeon Walkthrough Guide
The Duality Dungeon from Destiny 2’s Season of the Haunted is one of the best endgame activities in the game. Like the Season it’s a part of, Duality is about exploring the depths of a character’s past: in this case, the past of exiled Cabal Emperor Calus. Duality delves into the pain deep in his heart, unearthing what he feels are his greatest failures and regrets.
This guide covers how to complete the Duality Dungeon, from its platforming sections and puzzle-solving to the three boss fights.
How to Complete the Duality Dungeon in Destiny 2 Season of the Haunted
Duality’s core mechanic is movement between two reality states: Calus’s main consciousness and the world of nightmares. The Dark realm is a deep crimson, and the world seems to be on fire or bleeding. We’ll call them Light and Dark realms. You’ll ring red nightmare bells to move between these two spaces.
If you’re in the Dark realm and you aren’t standing within the circle surrounding the bell, you and any teammate who is not in the circle will immediately die. In boss fights, you’re on a timer called Nightmare Collapsing whenever you're in the Dark realm. If you don’t activate the bell while standing in its circle when time runs out, you are your whole fireteam will die.
You’ll also be placing Standards tied to symbols familiar to players who remember the earlier Leviathan activities:
Every encounter uses and builds upon the identification and gathering of these symbol Standards, and collecting them gets more difficult.
Duality Platforming Section 1: Learning the Ropes
When you first spawn into the Duality Dungeon, stand on the circle around the effigy of Calus. After Eris finishes speaking, you’ll drop into the dungeon itself.
You’ll start in a room with no apparent exit. Look through the barred window and see the red bell across the room.
It takes about 4,000 damage to activate it on Legend difficulty.
Once the bell activates, you’ll be transported into a straightforward Dark realm space. Your only job here is to run across the long hall and ring the bell on the other side.
Ringing the bell will put you back into the Light realm version of this room.
Now you need to make your way up the scaffolding to a platform near the ceiling at the other end of the room. Run to the other end of the room and jump on the platforms on either side of the main staircase.
Next, jump on the small, thin connecting strut between the two main pillars.
From there, jump onto the higher strut, then onto the side platform where the Psions have been shooting. Run back to the other end of the room and jump onto the struts between the columns.
From the highest strut, jump onto the platform jutting from the far wall that faces the bell at the other end of the room.
Once you’re on the final platform, shoot the bell across the way. You’ll spawn into the Dark realm on long struts with a few orange-bar Legionnaires, but you can safely ignore them. Make your way across the room and activate the bell.
Back in the Light realm, you’ll see a pack of Psions and two Centurions. Jump onto the left platform where there’s another bell behind the leftmost grate. Shoot it.
Turn around once you’re back in the Dark Realm. Jump across to the platform there, then look down. You need to jump down to the platform far below you, then through the hole in the wall at the far right of the room.
From there, navigate around the pipes to reach the next bell.
Ring it, then turn around and drop off where you’re standing. Go to the room at the bottom of the drop, jump into the opening nearby, and then go through the Calus’s face door with a tongue stretched across the threshold.
A collection of Colossus, Legionary, and Psion enemies are in the large bed chamber beyond. Clear all of them to open the bay door in the center of the room’s floor.
The first boss fight is below.
Duality Sorrow Bearer Boss Fight: Setting the Standards
This fight is against the Nightmare of Gahlran, the Sorrow Bearer, and teaches the mechanics of upcoming encounters. You start the fight by ringing bells at either end of the room.
- Top Left: Cup
- Top Right: Sun
- Bottom Left: Axes
- Bottom Right: Dog
Ringing the bell will send you into the Dark realm, and the doors to either side of the bell will be open. Two rooms will have enemies, and two will be empty, which will vary each time you start this phase of the fight.
The enemies in the room will primarily be War Beasts, but there will be a single orange bar Psion called a “Standard Bearer.”
Defeating this Psion spawns a Standard Essence paired with one of the four symbols mentioned above.
Collect both Standard Essences, which will extend your Nightmare Collapsing timer by about 20 seconds.
Head back to the bell and ring it to return to the Light realm. The bell will then be immune and covered in red energy. Soon after you arrive, two orange bar Incindeor enemies will spawn called “Honored Bellkeepers.”
You must kill both at each end of the arena to activate the bell they’re near. Plant both Standard Essences at their proper symbol and the door to open, revealing a group of War Beasts and a single orange bar Colossus. Head inside the room and activate the bell, or have your third teammate outside the Standard rooms do so.
You'll be trapped inside the Dark realm, and six Visions of Gahlran will stand between you and the exit.
Make your way to the other end of the room, defeating the Visions as you go. Your teammate in the other room will be doing the same.
Once all six Visions are defeated in both rooms, Gahlran will become vulnerable to damage. Use whatever you’re comfortable with to do damage.
It’s possible to beat Gahlran in one damage phase, but if you don’t, repeat the steps outlined above to activate another damage phase. Repeat as many times as needed to put Gahlran down for good.
Duality Platforming Section 2: Across the Chasms
With Gahlran dead, the door in the middle of the arena floor will open. Grab your loot and drop down. You’ll arrive in a large, purple-lit room. Follow the hallway out and traverse your way through the machines. At the other end of the room will be an open passage.
Take it up and to the right. When you reach the exit, jump onto the platform above you and follow the path that continues upward. You'll need to turn left and jump across a chasm to a thin platform, then turn right and go down a brightly lit tunnel.
You’ll make your way to a cavernous room with coffins set into the wall over a bottomless pit, and several sets of scaffolding with enemies on them. Look down and to your left as soon as you enter this room. There will be a scaffold with some Legionaries and Phalanx on them.
Jump down and then across to a small jut of metal across a small gap. There will be a lever that extends several coffins outward to be used as platforms.
Make your way up the coffins. Turn to the right when you can go no further and jump across the two small metal struts and then to the platform on the other side of the room. At the far end of the platform is another lever. Flip it to extend additional coffins on the other end of the room. Climb these and open the door to the left of the final extended coffin.
Continue until you reach a large room with Cabal statues and a bell in the middle on a raised platform.
Duality Puzzle Section: Unlocking the Vault
Before you ring the bell, head down into the room and look at the positions of the statues. One of them will always be facing the bell. This is the 12 o’clock statue and the one you’ll use as a guide to finish the puzzle.
The remaining statues will be rotated in some way. The direction of the rotation will determine how many times you have to turn a switch behind the statue in the Dark Realm.
If the statue is facing:
- Right: Three turns
- Back: Two turns
- Left: One turn
- Front: Zero turns
Once you note which statue is turned which way, ring the bell. In the Dark realm, all the statues will be facing the bell, forcing you to remember which way they were turned. Head to the backside of each statue to see a knob in the shape of Calus’s face.
Use the 12 o’clock statue as a guide to turn each knob the number of times delineated by the Light realm statue’s direction.
If you do everything right, you’ll hear a deep tone. Head back to the Light realm, and the door beneath the bell will open, allowing you to drop into the vault. There are no timers or other wipe mechanics here. If you made a mistake when you’re back in the Light realm and the door isn’t open, there’s nothing stopping you from going back into the Dark Realm and trying again.
Duality Vault Boss Fight: Unlocking the Truth
When the encounter starts, a boss will spawn and go immune. Two symbols will appear on the central platform, showing which you’ll need to collect the proper standards from within the Dark Realm.
When the encounter starts, the bells at each end of the room (Top for the one at the top of the stairs, Bottom for the one without stairs) will be immune. You need to kill the Bellkeepers on the opposite end of the room from the bell you want to activate.
Kill both sets of Bellkeepers, make a note of which symbols are present, and position yourself near one of the four barriers at the four corners of the room.
Each barrier will have a symbol on it:
- Bottom left: Sun
- Bottom right: Cup
- Top right: Axes
- Top left: Dog
Ring the bell and enter the Dark realm, and the arena will shift. The walls near the smaller symbol walls will vanish, opening up an upper area. You need to kill everything in the upper area, including an orange-bar Colossus at the top of the space to cause the Standard Bearer, an orange-bar Centurion, to spawn. Kill it, grab the Standard Essence, and book it back to the bells.
You’ll need to kill another set of Bellkeepers, again at the opposite side of the bell itself. If you’re running as a fireteam, leave someone in the middle to clear the bell and keep the mobs under control.
Should you be running Duality solo, you’ll only have time to collect a single Standard, and the timing is very tight for collecting it, killing the Bellkeepers, and ringing the bell. Even on my efficient clears, I only had about ten seconds left on the Nightmare Collapsing timer.
Plant the two Standards in the Light realm, and the boss will be vulnerable. Kill it however you like, and a second one will spawn. Repeat the process another two times to complete the encounter and the vault door on the floor will open. Drop down to get yourself some loot.
Duality Platforming Section 3: The Path to Regret
Beyond the loot room, you’ll soon reach a gilded treasure chamber, past which you’ll enter another treasure room with a large white fabric-cloaked box in its middle.
Head to the opposite side of the room and stand on the platform leading away from the box. Look to the left to see another bell. Ring it and enter the Dark realm.
You’ll spawn near a few War Beasts and a Centurion, but you can ignore them and jump across to a set of struts to your right.
Another door to the right will lead you to the next bell. Ring it, then take the small hallway out of the chamber. Follow the path until you reach a bell, which, once rung, will have you jumping across a set of struts to another bell.
Once back in the Light realm, make your way up through the platforms until you reach a door that opens back into the room with the white-cloth-cloaked box. This time, you’re near the ceiling, and when you turn right, there will be more struts with enemies wandering about.
Jump across and head through the open door at the other end of the room.
Continue making your way up until you have to head down a purple-colored tunnel. Just beyond it will be an enormous room with support struts and a red-lit opening in the distance.
Turn to the right and jump across the platforms, keeping to the wall as much as possible. Make your way to the red opening and drop down into the room beyond.
Nightmare of Caiatl, Princess-Imperial Boss Fight: The Culmination of Knowledge
Your final trial is the Nightmare of Caiatl, and defeating her will take all the skills you learned from the last encounters.
Two symbols will be near two of the four large chains when you start the fight.
The symbols are also above four platforms at the room's four corners.
- Bottom left: Dog
- Bottom right: Cup
- Top Right: Axes
- Top Left: Sun
There are endless hordes of enemies that swarm during this encounter, so clear what you can and defeat all the Bellkeepers that appear, then go into the Dark realm.
Each of the symbol platforms will now be over a bottomless pit, and a Standard Bearer Psion will appear at each of them. If you kill the correct Standard Bearer, you’ll be given more time and access to the Standard Essence. If you kill the wrong Standard Bearer, your timer will be reduced to about ten seconds.
With both Standard Essences in hand, kill the two sets of Bellkeepers, and ring the bell to return to the Light realm. More mobs will appear, so clear them at your choice and set the two Standards. Repeat the process with the two new symbols that appear, and look to the chains near the Standards.
All four Standards placed, the gem in the chains will glow red.
Shooting the gem enough rings the massive bell at the top of the room and sends the Nightmare of Caiatl into the Dark realm, starting the damage phase. Shoot the last remaining small bell to reach the Dark realm before she does.
There will be three sets of Bellkeepers once you arrive in the Dark realm, and when Caiatl arrives, she’ll begin moving toward one of the three bells. If you haven’t cleared the Bellkeepers by the time she reaches the bell, she’ll leave the Dark realm, end the damage phase, and force you to do the symbol collection phase again.
If the bell is clear, wait until Caiatl is close to it and immediately stand within the circle around the bell. Ring it, and she’ll be stunned, and you’ll receive an eleven-second buff called Waking Resonance. The buff will allow you to do damage to her. Without it, you’ll be doing dozens of points of damage, not thousands.
Once you complete the first damage phase, Caiatl will move to one of the remaining bells. You can stop her progress briefly by baiting her to slam the ground with her foot, giving you a few extra seconds to reach the bell.
Repeat the damage steps outlined here until you’ve used up all three bells, and unless you complete the encounter in one set of bells, the whole process resets. Complete the symbol collection and damage phases as often as you need to take Caiatl down. Once the Nightmare of Caiatl is defeated, you’ll automatically warp back to the start of the dungeon for your final collection of loot.
Congratulations, you’ve officially completed the Duality Dungeon in Destiny 2 Season of the Haunted. It’s quite a ride and has some of the best loot available in the game, including the Stormchaser Linear Fusion Rifle and much more.
We’ve covered dungeons in the past, most notably the Grasp of Avarice for the 30th Anniversary Celebration, where you get the Gjallarhorn. Our Destiny 2 guides hub has plenty of other topics, so head there next.