How to Complete the Duality Dungeon (Destiny 2)
This article is a reference guide and walkthrough for the Duality Dungeon.
In each section, we’ll go over the general mechanics of the fight, recommendations for weapons and subclasses, and lastly some tips to consider to make each encounter easier.
To make sure you’re taking on this dungeon with the best weapons, don’t miss our PvE exotics tier list.
If you’re looking for builds for your class, be sure to also check out these guides:
The main mechanic of this raid revolves around Bells. These objects are the way in which you and your team transport between each of the two realms, hence the name Duality.
For the sake of this guide and the reference to Yu-Gi-Oh, the standard colored realm will be referred to as the “Normal Realm”, and the red-tinged realm will be referred to as the “Shadow Realm”.
The Shadow Realm is a copy of the Normal Realm with only a few differences.
To transfer from the Normal Realm to the Shadow Realm, the bell must be shot. When the bell is shot, the entire fireteam is sent to the Shadow Realm in the same positions they are standing in.
To go back to the Normal Realm from the Shadow Realm the bell is shot again, but the fireteam must be standing within a circle around the bell. If a player is outside the circle, they will die.
The first portion of the dungeon introduces you to this mechanic through a jumping puzzle. To get through this portion of the dungeon in the initial Normal Realm area, ascend the beams crossing the room to shoot a bell at the top highlighted in the picture below.
From here the main gist is to shoot a bell in the Normal Realm typically through grates at a distance, and then in the Shadow Realm jump through obstacles and fight through enemies to get close to the bell that was shot from afar in the Normal Realm, and shoot it up close to transfer back.
- Snipers and Shotguns only take one shot to activate the bell. If in a rush you can use one of these weapons to activate the bell quickly.
- Rocket Launchers and explosive damage activate the bell. Be careful not to accidentally activate the bell through explosive damage if you are shooting enemies next to the bell with area of effect damage.
- If you die to the bell in the Shadow Realm by not being in the designated circle, your revive will be available in the Normal Realm. If the team is in a rush and one player is far from the bell you can actually sacrifice them to prevent a team wipe, and then pick up a revive in the Normal Realm.
The Return of Gahlran
Our first true boss fight is against the nightmare of Gahlran. The bell mechanic is active here, but a new standard bearing mechanic is also involved in this fight. The standard-bearer mechanic uses the same symbols from the original Leviathan raid which are Sun, Chalice, War Beast, and Axes. Gahlran is only in the Shadow Realm and is immune until 2 standards are activated in the normal room and all of the Shadows of Gahlran are defeated, we’ll get to this next.
To begin the fight, transport your team to the Shadow Realm via one of the available bells. In the Shadow Realm, you will be looking for Psion standard-bearers. There will be 2 Psion Standard Bearers you are looking for which will be in 2 of 4 rooms in the corners of the area.
These rooms will be given away by the presence of war beasts. For this fight, you have a limited amount of time in the Shadow Realm before it collapses, and this timer is extended by 15 seconds when a Psion Standard Bearer is defeated. Once these Standard Bearers are killed, a Standard will be dropped representing one of the 4 emblems (Chalice, Sun, Axes, War Beast). One player can pick up multiple Standards, but if you die with a Standard buff it will be lost.
Once these Standards are acquired they are to be taken back to the Normal Realm via a bell. The typical strategy is to have 2 players collect a Standard of their own and the third to kill the Bell Keepers to make the bell back to the Normal Realm available for use.
Once back in the Normal Realm with the newly acquired Standards, these Standards will be deposited into a slot with the matching symbol that will be in any of the 4 corners of the room. Once the Standard is deposited the doors behind the symbol will open. Kill the enemies inside and you can transfer back to the Shadow Realm. When transferring be sure to be in this newly opened room.
When transferring to the Shadow Realm while standing in one of the newly opened rooms you will be transported into a new area of the Shadow Realm with multiple enemies that are weaker copies of Gahlran, referred to as Visions of Gahlran. All of these enemies in both rooms must be killed to make Gahlran damageable. The typical setup is to have one player in each of the 2 open rooms and have the third player in the center to kill the Bell Keepers.
Once all the Visions of Gahlran are killed, Gahlran himself can be damaged. Remember, that this form of the Shadow Realm has a timer and the Bell to the Normal Realm must be taken before this timer is up, so you have a limited amount of time to kill the Visions of Gahlran, the Bell Keepers, damage Gahlran himself, and leave the Shadow Realm using the Bell. This process will be repeated until Gahlran is defeated.
Gahlran Recommended Loadouts
Swords – Swords work very well here as they can quickly kill Bell Keepers, Visions of Gahlran, and then damage Gahlran himself. If using a sword, damage from enemies is your main concern. Lament is a great option due to its ability to heal, if using Falling Guillotine or another option be sure to monitor your health and heal as needed via a rift, classy restoration, sunspots, etc. Heartshadow is a solid option as you can go invisible if you need to avoid damage.
Witherhoard – Pairs with legendary swords. You can shoot Witherhoard and swap to a sword for damage while it ticks.
Rocket Launchers – Due to Gahlran being mobile, these weapons are an easy means to hit him with splash damage.
One person to have a long-range weapon to deal with sniper Psions – Long-range primary weapons are weak for damage, and snipers are hard to get value in terms of Gahlran damage due to his mobility and being a melee boss, but having one fireteam member with a weapon that can take out the snipers outside the arena goes a long way for surviving.
Damage supers work well here (Blade Barrage, Nova Bomb, Shadowshot) for quick damage and then using weapons the rest of the damage phase.
Burning Maul – This super was just buffed and is actually a great option with Synthoceps. If you build stacks of Roaring Flames and make sure to be surrounded by 3 enemies this super will deal a lot of damage and keep you healthy. Once the super is over you can use the throwing hammer over and over the rest of the damage phase.
Well of Radiance – This is the safe option if you have difficulty staying alive during damage. This super keeps you alive, and has a damage buff, but that damage buff can be achieved by other means with the added bonus of a high damage quick cast super.
- You can alter the order of mechanics to get extra damage phase time. If in your first run of the Shadow Realm you kill both Standard Bearers and pick up one Standard, reenter in the side room to kill the Visions on one side, and then collect the other standard and leave. Then when you enter a 3rd time through a side room you can kill the second set of Visions and a new Standard Bearer that will spawn in for an extra 15 seconds of damage.
- The Glaive of Dreams Season 17 artifact mod will double the duration of the Unstable Essence Buff that increases Gahlran damage by 50% which is dropped from the Visions of Gahlran.
- If you plan on using weapons only for damage on Gahlran, feel free to use an ad clear super to quickly kill the Visions of Gahlran for a longer damage phase.
- Familiarize yourself with the layout of the room. When killing the Visions of Gahlran it is easy to get turned around and waste time looking for the exit to the main room.
Use the Visions of Gahlran or the copious amounts of enemies to stack buffs such as Roaring Flames, make wells, etc. to deal extra damage to Gahlran.
Journey to the Vault
The interim between Gahlran and the vault consists of jumping puzzles similar to before. There is also a room with 4 statues. Some of these statues will be turned. Note which statues are not facing the center. On the outside of the statues are buttons that rotate the statues only when in the Shadow Realm pictured to the right.
Transport to the Shadow Realm, hit these buttons to turn the statue 90 degrees (so twice to turn the statue 180 degrees) so that all of the statues are facing the center when going back to the Normal Realm.
Once this is done the door beneath the bell will open for you to continue. In this room there is a secret chest which will contain loot you have already acquired. The chest location is to the left of the room behind an open on the balcony and can be seen here:
Opening The Vault
This next encounter is a mini-boss encounter that repeats itself 3 times. The Layout of the room is similar to that of Gahlran. 4 of the same symbols are in each corner, 2 potential bells, and a boss in the middle.
Here there are 3 separate bosses in the normal realm that each spawn in individually during one of the 3 phases in the encounter. In the Normal Realm, there are 2 symbols that can be seen being projected from the ground in the center of the room.
These symbols can be matched to walls placed in the 4 corners of the room. When Bell Keepers are killed and the bells are available, have 2 players each go to the corner of one of the projected symbols. The third player can kill the Bell Keepers in the middle.
The players who are hunting for the symbols will go up a set of stairs towards the outside of the room to see an open room with enemies and a yellow bar enemy at the end of the room on top of another set of stairs. Just like in the Gahlran fight there is a time limit in the Shadow Realm which is extended by killing a Standard Bearer so you have to go quickly.
Once all of the Phalanx cabal and the yellow bar enemy at the top of the stairs a standard-bearer will spawn. Kill the Standard Bearer to collect that symbol’s Standard. Head back to the bell that is available and deposit the Standards. This will open up the boss in the middle of the Normal Realm for damage. Once the boss is defeated one third of the lock will be opened. Repeat the process 2 more times in order to completely open the vault.
Vault Recommended Loadouts
Multi-Kill supers such as Hammer of Sol and Golden Gun are good options to clear out the Phalanxes and Standard Bearer as there is no time limit to boss damage.
Swords are good options to clear the necessary enemies out quickly.
There isn’t a need for long-range weapons in this encounter.
- To spawn the Standard Bearer you will need to kill all of the Phalanxes and the Honored Colossus at the top of the stairs in the Shadow Realm.
- The central area of the Shadow Realm is a pit that will kill you, so when shooting the bell to transfer do not stand in the center of the arena.
- There is no time limit to kill the mini-boss. So take your time and feel free to save ammo for the time-limited Shadow Realm.
On the Road Again
Before the final boss, there is a little more traveling to do. On the way there, is another hidden chest that has already acquired loot. It can be found in the room with the glossy purple floor in the center and treasure and gold around the outside under one of the bridges through a small opening pictured here:
Nightmare of Caiatl
Here we have Calus’ final nightmare which turns out to be his own daughter. This fight has most of the same mechanics as the other fight but with a few twists. In the Normal Realm of this fight there will be 2 icons projected of the emblems that have been collected through the dungeon (Sun, Chalice, War Beast, Axes). The emblems are also represented by a platform in each of the 4 corners.
The 2 projected emblems are to be the collected Standards in the Shadow Realm. The Standard Bearer for these symbols corresponds to the symbol above the platform. To collect the Standards the Standard Bearer for the corresponding symbol that will spawn on the platform in the Shadow Realm must be killed.
Just as before the Bell Keepers must be killed to make the Bells available to transport back to the Normal Realm. In this part of the fight, 2 players should collect Standards and one can kill Bell Keepers. Have the Standard retrieving players stand on top of the platforms with the projected symbol to immediately transport next to the Standard Bearer.
Once you return to the Normal Realm the players with the Standards need to deposit them and this process is repeated until there are 4 Standards deposited.
Now that there are 4 Standards deposited it is time for the damage phase. To initiate the phase any of the red chains behind the deposited Standards are to be shot at that is highlighted in the picture. This will ring the large bell in the back of the room and transport your team and Caiatl to the Shadow Realm. From here Caiatl will spawn in at the top of the room and run to one of the 3 bells.
If Caiatl runs to a bell she teleports back to the Normal Realm and the damage phase is over. In order to prevent her from teleporting you must ring a bell while she is near it. 2 Bell Keepers are by each bell, making 6 total. If 2 paired Bell Keepers are defeated, that bell is available to be shot to stun Caiatl. Once Caiatl is stunned you can damage her with meaningful damage due to the Waking Resonance Buff. Make sure you have this as you can damage her without the buff, you will just do very little damage.
This is similar to the Atheon fight in Vault of Glass in Destiny 1 in which you can damage Atheon for negligible damage, but with the Time’s Vengeance Buff you deal damage that will actually do something to his health bar. Caiatl will go to all 3 bells if you are able to stun her when able, and the Waking Resonance buff is given every time she is stunned. Once Caiatl teleports back the fight will repeat itself.
Caiatl Recommended Loadouts
High Damage Supers – Blade Barrage, Nova Bomb, and Shadowshot are good options.
Well of Radiance – The only downside to this super is that the damage phase is broken down into 3 subsections. But for one of those 3 subsections, this super is great to give the fireteam a boost to damage and make sure you stay alive from the snipers on the platforms.
Swords – Once again swords are a great option. Great tool for killing the Psion Standard Bearer, the Bell Keepers, and damage is up close to a stunned target. Lament, Falling Guillotine, and Heartshadow are good options.
Combat Bow – A bow is a solid option for one player to have to deal with snipers during the damage phase and in the Normal Realm. Be sure to not shoot the Psion Standard Bearer Snipers if they are not of the correct symbol as you will lose time in the Shadow Realm
Witherhoard – No surprise this is on the list. It is great to collect the Standard by shooting it at your feet as the Standard Bearer spawns in and to deal damage to Caiatl who stands perfectly still.
Stormchaser – This weapon pairs perfectly with Witherhoard. During damage, Caiatl sits still so headshots are very easy to get with a precision weapon like this.
- When Caiatl is running towards a bell you can run near her to force her to perform a stomp which will slow her down, giving you more time to kill Bell Keepers and/or prepare the bell she is running to.
- You can wait before grabbing the Standards, as if you die with the Standard it is lost. The Colossus does a lot of damage and can stall your run if it kills you right after picking up a Standard.
- Use the Bell Keepers during the damage phase to create Elemental Well or Orbs of Light for bonus damage mods such as High Energy Fire or Font of Might.
Duality Dungeon Rewards Loot Table
To end the guide we have what weapons and armor are from what encounters. The loot is farmable as each encounter can be done multiple times with a loot drop.
Each weapon’s element is the highlight color with the exception of Heartshadow which is an exotic void sword.
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