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Duality

Released
Location
Derelict Leviathan
Power
300 / 300Combatant / Activity
Route
3 encounters

Full route / first editionSource-reviewed · Not yet verified in game · Updated · What changed

Change history (2)
  1. Cosmetic

    Encounter list: The encounter list now also links the approach and traversal sections.

  2. New

    Whole guide: Published with the full route, roles, recovery and solo notes.

Main changes since the September 2026 rewrite, newest first. Corrections fix something that was wrong; site-wide layout changes aren’t listed. Source review means checked against the cited sources, not played.

Prepare for the whole route.

Prepare for close combat

Bring healing, fast Major removal and a reliable damage option. Check access and current modifiers before launch. This route covers the standard dungeon.

Agree on calls

Use Chalice, Sun, Axes and War Beast. Assign two Standard runners and one bell operator. Call the return bell and confirm everyone is inside before firing.

Bells, Standards and survival

Bells, Standards and survival
MechanicExecution
Entering NightmareShooting an available bell transfers everyone at their current position. Check that your landing surface exists in both realms.
Returning to wakingEvery survivor must stand inside the ringing bell’s circle. Players outside die.
Nightmare CollapsingLeave before the lethal timer expires. Correct Standard Bearers add time; wrong targets in the Vault and Caiatl remove it.
BellkeepersKill the linked Incendiors to unlock an exit. Clear their explosive backpacks before gathering.

APPROACH / THE MINDSCAPE

Use each realm to reach the next bell.

Listen to Eris at the Calus statue and descend. Shoot the first bell through the bars, cross to it in Nightmare, then return from inside its circle. Climb the waking chamber’s beams to the upper bell. Alternate realms through the gated passages and wall openings; clear the room beyond the giant Calus mouth to open the floor to Gahlran.

Route reference ↗

Encounter list ↑
The waking mindscape and its bell
The waking mindscape and its bellBungie · Duality press kit

The encounter route

01 / ENCOUNTER

Nightmare of Gahlran, Sorrow Bearer

Recover two Standards, clear both Vision corridors, then damage.

Encounter list ↑
Nightmare of Gahlran, Sorrow Bearer, Duality
Nightmare of Gahlran, Sorrow BearerBungie · Shacknews / Sam Chandler

Encounter sequence

  1. Recover the Standards

    Ring into Nightmare. Find the two Psion Standard Bearers in the four side rooms, defeat them and collect their Essences. Kill the Bellkeepers at the opposite end from your entry bell. Gather at the unlocked bell and return.

  2. Enter the opened rooms

    Deposit each Essence at its matching waking symbol. Clear the enemies behind both doors. Put a runner inside each opened room before ringing into Nightmare again.

  3. Clear the Visions

    Each runner defeats their corridor’s Visions of Gahlran. Both corridors must be cleared to expose the boss. The center player unlocks the return bell.

  4. Damage, then escape

    Attack Gahlran while vulnerable. Stop with enough time for everyone to reach the bell circle and return. Repeat Standards and corridors until he falls.

If the attempt breaks down

A dead carrier loses their Essence. Bring back what you can and collect the missing one on another trip. A locked corridor still contains a Vision; an immune boss means the other corridor is unfinished.

Encounter source & visual reference ↗

TRAVERSAL / THE CRYPT

Extend the tombs and turn the statues inward.

Drop through the reward room and follow the pipes. In the chasm, cross to the low lever, climb the extended tombs and cross back to the next lever. Follow the new platforms to the upper exit. Brake before the chute’s landing, then continue to the four-statue room. Inspect their facing directions in waking. In Nightmare, switches behind their bases rotate them a quarter-turn counterclockwise. Return and check: all four must face the center to open the floor.

Route reference ↗

Encounter list ↑

02 / ENCOUNTER

Unlock the Vault

Two requested Standards expose one guardian. Complete three rounds.

Encounter list ↑
Unlock the Vault, Duality
Unlock the VaultBungie · Shacknews / Sam Chandler

Encounter sequence

  1. Read before ringing

    Read the two central symbol projections. Locate the matching corner markings in waking; do not assume the room uses Gahlran’s layout. Move toward the required corners, then enter Nightmare.

  2. Earn the two Essences

    Clear each matching corner’s enemies and Colossus to spawn its Standard Bearer. Kill only the requested bearers and collect the drops. Avoid the open central pit.

  3. Return and defeat the guardian

    Unlock the bell, regroup inside its circle and return. Deposit both matching Essences. Defeat the now-vulnerable Nightmare in waking.

  4. Complete all three locks

    Read the new pair and repeat for the remaining two guardians. Six total deposits open the vault.

If the attempt breaks down

If time is short, return with one Essence and make another trip. Recheck the active symbols each round; killing an unrequested bearer can leave too little time to escape.

Encounter source & visual reference ↗

TRAVERSAL / THE DEPTHS

Follow the bells to the Dark Shrine.

Use the bell behind the back-left bars, cross the Nightmare platforms and reach the opening above. Return to waking to climb the shaft. Continue alternating realms through the rafters, then descend. At the final chasm, follow the right-hand wall ledges toward the red doorway.

Route reference ↗

Encounter list ↑

03 / ENCOUNTER

Nightmare of Caiatl, Princess-Imperial

Deposit four Standards, ring the great bell and stun Caiatl at each small bell.

Encounter list ↑
Nightmare of Caiatl, Princess-Imperial, Duality
Nightmare of Caiatl, Princess-ImperialBungie · Shacknews / Sam Chandler

Encounter sequence

  1. Collect the called symbols

    Read the two projections by the chains. Unlock a small bell and enter Nightmare. Kill the Psions on the matching symbol balconies, collect their Essences, clear Bellkeepers and return together.

  2. Finish four deposits

    Deposit at the matching symbols and collect the next requested pair. After four deposits, shoot a glowing chain gem to ring the large bell and start the damage transition.

  3. Intercept Caiatl

    In Nightmare, kill all three Bellkeeper pairs promptly. Watch which bell Caiatl approaches. Gather inside that bell’s circle and shoot it when she is close enough to stun. Nearby players gain Waking Resonance.

  4. Move with the boss

    Damage during the stun, then follow her to the next bell. Repeat for up to three stuns. If she reaches a bell unstunned, she escapes and ends damage early. Repeat the collection cycle if needed.

If the attempt breaks down

Do not ring a damage bell just because it is unlocked. Wait for Caiatl to enter stun range and teammates to gather. A player can briefly bait a stomp to buy travel time, but should keep clear of backpacks.

Encounter source & visual reference ↗

Keep a safe next move.

Budget every Nightmare trip

Collect one Standard at a time when needed. Gahlran’s two Vision corridors can be handled across separate trips; both must be cleared before damage. Reserve time for Bellkeepers and the return journey.

Practice the final bell sequence

Prioritize Caiatl’s next bell over extra damage. Remove backpacks from your path. For solo flawless, start fresh and keep the run uninterrupted; rehearse the crypt jumps first.

Choose optional stops before launch.

Heartshadow

The Exotic sword can drop from Caiatl. Its catalyst has a separate Nightmare-and-Standard route after obtaining the weapon; consult the linked optional guide.

Optional detours

Repressed Memories and two hidden chests require stops along the route. Master and reward availability depend on the activity card. This guide does not claim a current loot table.

Keep the reference close.

Released 27 May 2022. This guide covers the standard clear. Source review excludes old Power targets, weapon rankings and reward schedules. Detailed optional routes are linked below.