The Duality Dungeon is a brand new endgame activity in Destiny 2 that will need to be completed to earn seven new weapons, a new Exotic ship, armor, and more. Like all dungeons in Destiny 2, Duality contains three encounters that simultaneously contain puzzles to solve and bosses to defeat. Additionally, the Dungeon also has a Master difficulty version available for Guardians to complete, with much tougher opponents and Champions awaiting the fireteam.
Duality takes place inside the mind of Calus tethered to an object aboard the Derelict Leviathan. As the activity brings players deeper and deeper into the Cabal's subconscious, Guardians can also find 12 Repressed Memory locations in the Duality Dungeon that expand upon the Emperor's backstory. While these memories can all be found on the first completion of the dungeon, some of them are located in places that aren't part of the intended pathway. Guardians will have to travel to every corner and crevice available in Calus's mind to find them all, and doing so will allow them to claim the Mind Heist triumph. With the triumph claimed, the odds of unlocking the new Heartshadow Exotic sword in the dungeon will further increase.
Throughout Duality, large red bells will need to be damaged so that transportation to and from the Nightmare realm can occur. This realm poses one of the biggest challenges in Destiny 2, Season of the Haunted because there are several times when the Nightmare is on the verge of collapse. If the fireteam doesn't make it to the next bell before it collapses then those left outside of the ring when the bell is rung will instantly die. There will also be times throughout the dungeon where Nightmare Bellkeeprs need to be defeated before the bell can be rung. If these enemies aren't defeated, then the fireteam will be trapped inside of the Nightmare realm when it collapses.
Destiny 2: How To Defeat The Nightmare Of Gahlran In Duality
Following the first jumping puzzle that introduces some of the aforementioned concepts, the fireteam will need to defeat the Nightmare of Gahlran. After rallying up, hit either ring either of the two bells in the arena to be transported to the Nightmare realm. The Nightmare of Gahlran's haunting presence is bound here in Destiny 2, but he remains immune for the time being. The fireteam needs to look for two Psions that can spawn in either the left or right rooms at the top or the rooms at the bottom. Defeat the Standard Bearer Psions, pick up the essence that they drop, and be sure to defeat the Nightmare Bellkeepers located opposite the bell that was rung to get to the Nightmare realm to return to the "real world." Bring the essence to the corresponding door in the real world, for example, bring the War Beast essence to the War Beast door. Dunk the essence, clear the enemies inside, and ring the bell with one teammate inside each of the two rooms.
After returning to the Nightmare realm, the teammates in the rooms should use an Exotic sword in Destiny 2 like Lament to quickly defeat the six Galhran copies and reach the end of the room. At this time, the teammate outside of both rooms should find the Nightmare Bellkeepers and defeat them to prepare the bell once more. After both sets of copies are defeated, the realm Nightmare of Gahlran can be damaged.
Since this boss will only deal melee damage, it's a great idea to have either a Warlock with Well of Radiance or Titan with Ward of Dawn on the team that can place their Super down, then unleash as much damage as possible with Lament or another sword before the Nightmare collapses. The best-case scenarios are that either two teammates run Lament while the third uses Divinity, all three use Lament, or everyone uses a powerful weapon like the Gjallarhorn Exotic Rocket Launcher with its Catalyst active.
If the Nightmare of Gahlran isn't defeated in the first damage phase then the fireteam will just need to repeat the aforementioned steps. Additionally, there is no timer in the real-world portion of the encounter, so the fireteam can farm the ever-spawning enemies to generate as much ammo as needed. Lastly, if a teammate loses their essence after dying, it can be picked back up in the Nightmare realm after defeating another Psion.
Destiny 2: How To Complete The Unlock The Vault Encounter In Duality
The second encounter of Duality is similar to the first, but there are three enemies that are initially immune in the real world who will need to be defeated. For this encounter, a good red bar clearing weapon, like the Calus Mini-Tool SMG in Destiny 2, will be critical for staying alive. Once the Nightmare Bellkeepers have been defeated and some of the enemies have been cleared, two glowing essences will appear. The fireteam can find the correct essence that corresponds with the symbols on the back of the lower-level wall, and once everyone is in place one Guardian can shoot the bell.
Upon arriving in the Nightmare realm, the fireteam members should be transported to the correct area of the map. Defeat the enemies that spawn in the hallway, including the Colossus at the top of the stairs. A Cabal Standard Bearer will appear that drop the correct essence once they are defeated. After both of the Nightmare Bellkeepers are defeated as well, the fireteam can return to the real world and defeat the first immune enemy. Afterward, the process repeats two more times before the encounter is cleared.
Not every Character Stat in Destiny 2 needs to be high for this encounter, but each fireteam member should seriously consider maxing out their Resilience stat to help survive the overwhelming amount of enemies that spawn. The Resilience stat received a major upgrade at the beginning of Season of the Haunted and now allows Guardians to resist 40% of PvE damage when it reaches the max tier.
Destiny 2: How To Defeat Calus's Greatest Shame In Duality
Calus's Greatest Shame is the final encounter of Duality, and it forces the fireteam to defeat a Nightmare of Caiatl. Once the encounter begins, three pairs of Nightmare Bellkeepers will spawn near the left, middle, and right bells in the arena. Defeating the corresponding pair will unlock that bell. A Riptide Fusion god roll in Destiny 2 with Auto-Loading and Chill Clip is great for this encounter because so many enemies are all bunched up as well. Similar to the second encounter, two symbols will appear corresponding with the essences that the fireteam needs to grab from the Nightmare realm. It's easiest to grab these essences by heading to the platforms with the corresponding symbols above them before ringing the bell as this will transport those Guardians directly to the Psion Standard Bearer.
After collecting the essences, defeat the Nightmare Bellkeepers to unlock the bell and return to the real world. Dunk both essences, then repeat the process with a new set of symbols. Auto-Loading Rocket Launchers such as Bump in the Night can make it easier to defeat the Nightmare Bellkeepers with the limited time available since the pair is often standing close to one another. Once the second pair of symbols has been dunked, the large battering ram in the center of the room will be hoisted upward. After one of the four chains has been shot, the battering ram will smash into the bell to begin the damage phase.
Both the fireteam and Caiatl will be transported to the Nightmare realm during the damage phase, along with six Nightmare Bellkeepers. Defeat the Nightmare Bellkeeprs as quickly as possible, then pay attention to which bell Caiatl moves towards. Ring the bell only while standing in the circle and when she is in front of it. This will simultaneously stun Caiatl and provide anyone standing in the ring with a damage buff. Fusion Rifles and Rocket Launchers in Destiny 2 with Auto-Loading can help Guardians make the most of the damage phase as the stowed weapons are automatically reloaded. The damage phase can be extended by ringing the next two bells at the appropriate time, and the whole process can be repeated as many times as it takes to clear the Calus's Greatest Shame encounter, completing the Duality Dungeon in Destiny 2.
Destiny 2 is available on PC, PlayStation 4, PlayStation 5, Xbox One, Xbox Series X|S, and Google Stadia.