How To Get Arc Circuitry In Destiny 2: The Definitive Guide To The Symphony Of Death Quest
To obtain Arc Circuitry, players must complete the K1 Revelation Lost Sector located in the Sorrow’s Harbor region of the Moon and loot the final reward chest. This item is a critical component of the Marrow's Elegy quest step, which serves as a foundational requirement for forging the Deathbringer Exotic Rocket Launcher. Success depends on completing the Shadowkeep campaign and the subsequent Memory of Sai Mota quest to unlock the necessary quest purification steps.
Essential Prerequisites and Gear Preparation
Before attempting to acquire Arc Circuitry, you must ensure your character has completed the primary Shadowkeep story arc. Unlike standard world drops or crafting materials, Arc Circuitry is a unique quest-bound item. It does not exist in the general loot pool and will only drop when the specific "Marrow's Elegy" quest step is active in your inventory.
To reach this stage, you must first finish the Lunar Spelunker bounty provided by Eris Morn, which requires clearing three specific Lost Sectors on the Moon: K1 Communion, K1 Logistics, and K1 Crew Quarters. Following this, you must complete the "Memory of Sai Mota" quest, which involves gathering necklace fragments by defeating Nightmares with Arc abilities. Only after these tasks are finalized and you have spoken to Eris Morn in her portal location can you progress to the Faculties of the Skull and subsequently the Marrow's Elegy step.
Mandatory Checklist:
- Expansion Ownership: Destiny 2: Shadowkeep must be active on your account.
- Campaign Status: Complete the "Beyond" mission and the "Memory of Sai Mota" questline.
- Quest Item: Ensure the "Marrow's Elegy" quest is in your Quests tab.
- Required Loadout: High-burst damage weapons (Linear Fusion Rifles or Rockets) and Unstoppable/Barrier Champion mods if running the Lost Sector on Legend or Master difficulty.
- Location: Sorrow's Harbor, The Moon.
- Estimated Duration: 15–20 minutes for the final run, excluding prerequisite campaign steps.
Step-by-Step Guide to Acquiring Arc Circuitry
The acquisition of Arc Circuitry is a linear process that culminates in a specific dungeon-style encounter within the Hive-infested tunnels of the Moon. Follow these technical procedures to ensure the item registers correctly in your quest log.
Step 1: Navigating to Sorrow’s Harbor
Spawn at the Sorrow’s Harbor landing zone on the Moon. Instead of engaging with the Altars of Sorrow public event, head toward the northernmost section of the map. Look for a large Hive structure that leads underground. The entrance to the K1 Revelation Lost Sector is marked by the distinct red "arch" symbol on a stone slab near a tunnel entrance. Follow the path deep into the lunar crust until the "K1 Revelation" location prompt appears on your screen.
Step 2: Engaging the Hive Defense Layers
The K1 Revelation Lost Sector is partitioned into three combat zones. In the first zone, you will encounter several Acolytes and a few Knights. You must clear all enemies to drop the first set of soulfire barriers.
Pro-Tip: Use a Void subclass or weapons with Volatile Rounds to quickly clear the groups of Acolytes. The high density of minor enemies makes this an ideal environment for area-of-effect (AoE) damage.
As you move into the central chamber, several Shriekers will activate. These are high-priority targets. You cannot damage the central crystals or the final boss until the Shriekers and the accompanying "Nightmare" enemies are neutralized. Ensure you are utilizing cover, as the Shrieker projectiles have aggressive tracking capabilities.
Step 3: Defeating the Nightmare of Arguth, the Desecrated
The final boss of K1 Revelation is a massive Ogre known as Arguth, the Desecrated. This boss is protected by an invulnerability shield that is tied to the surrounding Hive crystals. To lower the shield, you must defeat the Elite Wizards that spawn on the side platforms.
Once the Wizards are down, destroy the glowing Hive crystals. This will make Arguth vulnerable to damage. Focus your Heavy ammo or Super ability on the Ogre’s critical point (the glowing eye). If you do not kill the boss quickly enough, the shield will regenerate, requiring another cycle of Wizard and crystal destruction.
Step 4: Looting the Cache and Extracting Arc Circuitry
Once Arguth is defeated, the barrier protecting the reward chest at the back of the arena will dissipate. Approach the chest and interact with it to open it.
Warning: Do not leave the Lost Sector via the map or fast travel immediately after the boss dies. You must physically open the chest to trigger the quest progression.
Upon opening the chest, the Arc Circuitry will automatically be added to your quest progress for "Marrow's Elegy." You do not need to pick up a physical engram; a notification on the right side of the HUD will confirm the acquisition. This item is virtual and resides within the quest step itself rather than your material inventory.
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Moon Lost Sector Technical Comparison
The following table compares the various K1 Lost Sectors on the Moon to help you distinguish K1 Revelation from the others required during the prerequisite "Lunar Spelunker" bounty phase.
| Lost Sector Name | Location | Primary Enemy Type | Boss Mechanic | Quest Relevance |
|---|---|---|---|---|
| K1 Revelation | Sorrow's Harbor | Hive (Ogres/Wizards) | Crystal Destruction | Arc Circuitry Drop Point |
| K1 Crew Quarters | Hellmouth | Fallen (Shanks/Vandals) | Heavy Shank Combat | Lunar Spelunker Step |
| K1 Logistics | Archer's Line | Fallen (Servitors) | Shielded Servitor | Lunar Spelunker Step |
| K1 Communion | Anchor of Light | Fallen (Captains) | Multi-phase Droids | Lunar Spelunker Step |
Troubleshooting Common Quest Failures
Even with the correct quest step, players occasionally encounter issues where the Arc Circuitry fails to drop or the quest does not update. Use the following diagnostic steps to resolve these common field issues.
Scenario: The Chest is Looted, but Arc Circuitry is Missing
- Root Cause: The "Marrow's Elegy" quest step was not active, or the "Memory of Sai Mota" was not fully turned in to Eris Morn's physical chest in the Enduring Abyss.
- Actionable Fix: Verify your quest log. If you have "Lunar Spelunker" or "Memory of Sai Mota" still active, you are too early in the chain. Complete those, visit Eris via the portal in Sanctuary, and loot the chest next to her to receive the "Faculties of the Skull," which then leads to the Arc Circuitry step.
Scenario: K1 Revelation Boss Shield Does Not Drop
- Root Cause: A hidden Acolyte or Wizard from a previous wave is still alive, preventing the crystal destruction phase from triggering.
- Actionable Fix: Sweep the upper ledges and the entrance corridor. Often, a single thrall or acolyte trapped behind a pillar will stall the encounter's scripted transitions.
Scenario: Cannot Access Sorrow's Harbor or the Lost Sector
- Root Cause: Character has not completed the opening "A Mysterious Disturbance" mission of the Shadowkeep campaign.
- Actionable Fix: Open the Moon map and look for the Shadowkeep campaign icon (a red skull). Complete the introductory missions until Eris Morn provides you with the "Lunar Spelunker" bounty.
Frequently Asked Questions
Can I farm Arc Circuitry to speed up the quest?
No, Arc Circuitry is a non-stackable quest item that is consumed upon acquisition to progress the "Marrow's Elegy" step. Once you have obtained it from the K1 Revelation chest, it disappears from the world loot pool for that character, and you must move on to collecting the Festering Bone and Ritualistic Bone.
Do I need to run K1 Revelation on Legend or Master difficulty?
Standard difficulty is sufficient for obtaining the Arc Circuitry. While running higher difficulties provides better endgame rewards like Exotic armor pieces, the quest item is guaranteed to drop from the basic version of the Lost Sector as long as the quest is active.
Where is the "Circle of Bones" mentioned in the previous quest step?
The Circle of Bones is located deep within the Hellmouth. You reach it by entering the Gatehouse and descending through the tunnels. It is a transitional zone where you must defeat a specific High Value Target (the Bone Collector) before the Arc Circuitry step in K1 Revelation becomes available.
What happens if I dismantle the quest by accident?
If you accidentally abandon the "Symphony of Death" or "Marrow's Elegy" quest, you can recover it at the Quest Archive kiosk in the Tower, located next to the Postmaster. Your progress is usually saved, allowing you to pick up exactly where you left off without re-running the entire campaign.
Is the Deathbringer still worth getting in the current meta?
The Deathbringer remains a top-tier Exotic for high-level PvE content due to its unique "Dark Descent" perk, which increases damage based on how far the void orbs fall before detonating. It is particularly effective against large, stationary bosses and for clearing massive waves of adds in Grandmaster Nightfalls.
Master Your Lunar Arsenal
Now that you have secured the Arc Circuitry, you are one step closer to wielding the destructive power of the Song of Death. Continue your journey across the lunar surface to finalize the remaining ritual components and claim your Exotic reward.
