To attempt this side quest, you need the Shadowkeep DLC expansion pack.
Talk toErisagain and accept theLunar Spelunkerbounty.
Complete three Lost Sectors across the Moon (K1 Communion,K1 Crew Quarters, andK1 Logistics).
Complete the final Lost Sector (K1 Revelation) in Sorrows Harbor.
At the end of the sector, look for an orange tunnel leading to a locked door.
Use theFirewall Data Fragmentto unlock it and obtainSai Motas Broken Necklace.
Go to Sorrows Harbor and defeat Nightmares using Arc abilities to collect20Necklace Scraps.
Return to the Sanctuary and enter the portal where you normally find Eris.
They tend to appear near the Fallen encampment.
Join theScarlet Keep Strikeand defeat Sulmakta the High Conductor on the second floor.
Complete theOf Darkest Harmonyquest step by defeating enemies.
Complete theChoir of the Damnedquest step.
Head back to theCircle of Bonesand defeatIr Airam the Deathsinger, then return toEristo obtain the Deathbringer rocket launcher.
What Can the Deathbringer Exotic Rocket Launcher Do?
The Deathbringer is an Exotic weapon exclusive to the Shadowkeep expansion.
The Deathbringer launches rockets that split into multiple projectiles for maximum range and damage.
Its intrinsic perk is Dark Deliverance, which shoots projectiles that can be detonated remotely.
Other perks include Volatile Launch, Alloy Casing, Dark Descent, and Composite Stock.
You need 125,000 Glimmer, 200 Baryon Bough, an Exotic Cipher, and an Ascendant Shard.
The Circle of Bones is located on the Moon in the Hellmouth.
All entrances to the Hellmouth lead to the Circle of Bones.
Look around the pit for the Withered Plumes weapon enhancement.
