How to complete the Destiny 2 Unfinished Business Exotic Quest

Destiny 2 Lightfall Deterministic Chaos Exotic Machine Gun — (Image credit: Bungie)

Complete the Destiny 2 Unfinished Business Exotic Quest in Lightfall to get the Deterministic Chaos Exotic Machine Gun. With Neomuna (sort of) saved, it's time to help Nimbus and Osiris take a look back through some of Rohan's lost research about the Vex that will (very slightly) help you better understand the Veil. It's not an especially long Destiny 2 quest, but this guide should speed things along, helping you quickly reach the special mission at the end and unlock Deterministic Chaos in all its rhythmic glory. I've laid out all the Destiny 2 Unfinished Business quest steps below and some tips to breeze through it.

Destiny 2 Unfinished Business Exotic Quest steps

Destiny 2 Lightfall Unfinished Business quest from Nimbus — (Image credit: Bungie)

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You’ll collect the “Unfinished Business” Exotic Quest from Nimbus while having your final chat with them to round off the Destiny 2 Lightfall campaign. Doing so will set you on a path of honoring Rohan’s sacrifice and then investigating some lost research about the Vex that the Cloud Strider started. With some help from Osiris and Nimbus, you’ll eventually get to play in a special mission and will get Deterministic Chaos – a new Exotic, Void-damage Machine Gun which we’ll explain more about further down. If you want to power through this quest, here’s a summary of all the Unfinished Business quest steps, events, and some tips to speed things along:

Go to the Hall of Heroes: Approach the massive white doors in the Hall of Heroes area of Neomuna to start a cutscene and open the Hall of Heroes proper.
Speak to Nimbus: You’ll learn that Rohan knew the Vex were working on a copy of the Veil years ago but you need to find Rohan’s research notes to investigate further.

Destiny 2 Lightfall unfinished business exotic quest collecting cipher qubits from Vex — (Image credit: Bungie)

Defeat Vex on Neomuna and collect the cipher qubits they drop, then collect five Destiny 2 Cloud Accretions: You need to collect eight qubits from dead Vex to perform a “data extraction” on a Cloud Accretion, so you’ll need 40 qubits in total. The best place to find Vex is Liming Harbor.
Head to Maya’s Retreat to get the last data packet: From Liming Harbor, head into the rocky cliffs to eventually reach Maya’s Retreat. Keep progressing until you reach the open area where you practiced with Strand and interact with the Vex conflux.
Survive the Vex attack then interact with the conflux again.
Meet Osiris and Nimbus in Radiosonde: Head back to Liming Harbor and then follow the waypoints through the large Radiosonde building to eventually the duo. You’ll learn that the Veil copy the Vex were building was actually the heart of the Black Garden, which was destroyed (maybe by you) at the end of Destiny 1’s main story.
Retrieve a Vex Compass from the Thrilladrome Lost Sector in Liming Harbor: To reach this Lost Sector, go to the north end of Liming Harbor, head inside the central building, jump to the upper level, and then climb inside a ventilation shaft. Loot the Lost Sector chest like normal to get the compass which will help you get inside the Black Garden.
Defeat 100 combatants in Ahimsa Park: Defeating enemies using your abilities provides additional progress.

Destiny 2 Lightfall unfinished business exotic quest typhon imperator trove with seed of silver wings — (Image credit: Bungie)

Retrieve a Seed of Silver Wings from the Typhon Imperator: Head inside Calus’s flagship and navigate through to the large treasure trove arena seen in the campaign mission Downfall. Defeat the Shadow Legion and then collect the seed from a wall on the upper ledge.
Return to Nimbus: Speak to them at Striders’ Gate. They’ll create Rohan’s passkey to get you inside the Black Garden and will mention your target is the Conceptual Mind that built the Black Heart.

Destiny 2 Lightfall unfinished business exotic quest what remains mission using deterministic chaos — (Image credit: Bungie)

Complete the “What Remains” mission: Head back to Maya’s Retreat to find the starting point for this Exotic mission. It’s pretty straightforward and along the way you’ll find and collect Deterministic Chaos. The mission will have lots of heavy ammo points giving you a good opportunity to take the Exotic Machine Gun for a test run. Defeat the Conceptual Mind Hydra boss to end the mission.
Go back to Nimbus: Osiris and Neomuna researchers can now start uncovering the secrets of the Conceptual Mind thanks to you.
Go to the Hall of Heroes: Head back to the hall and interact with Rohan’s memorial for one last cutscene to cap off the quest.

Destiny 2 Deterministic Chaos

Destiny 2 Lightfall Unfinished Business Exotic Machine Gun inspect screen — (Image credit: Bungie)

Congratulations on completing the Destiny 2 Unfinished Business quest! You’ve now got the Deterministic Chaos Exotic Machine Gun to use freely in your loadouts, except… it’s not spectacular. It might be hard to justify taking up your Exotic slot, but it’s Void debuff potential means it could certainly work in specialized Void builds and it’s rhythmic firing makes it fun to use to use. Here's how Deteministic Chaos works:

Heavy Metal: While holding down the trigger, every fourth bullet fired applies the weaken debuff, increasing the damage a target takes when affected.
Vexadecimal: While holding down the trigger, every fourth Heavy Metal shot (so every 16th shot) applies the volatile debuff, causing the affected target to explode after taking further damage.

If you want to learn more about what we feel are the best Destiny 2 Exotics, we can help you here!