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Destiny 2 Lightfall: How to get the Deterministic Chaos exotic

Get the Deterministic Chaos exotic weapon in Destiny 2 with this full Unfinished Business quest guide

Destiny 2: Lightfall introduces a host of new weapons to spice up your arsenal, including some interesting new exotic options. One of them, Deterministic Chaos, is available straight after finishing the campaign for anyone prepared to jump through a few simple hoops. 

If you’re a fan of Void builds that lean into the excellent Volatile Rounds, this brand new heavy machine gun looks just the ticket. So how do you get your hands on it?

Unfinished Business quest steps


The Deterministic Chaos exotic heavy machine gun can be obtained by completing a quest given out by Nimbus after the end of the Lightfall campaign. Here is a quick summary, and then we will break down any confusing or difficult steps. Start off by speaking to Nimbus to obtain the Unfinished Business quest line. After that:

  • Go to the Hall of Heroes
  • Visit Nimbus again
  • Collect cipher qubits from the Vex and use them to extract Rohan’s data from Cloud Accretions in Neomuna
  • Locate the final data packet in Maya’s Retreat
  • Regroup with Nimbus and Osiris in Radiosonde
  • Defeat 100 enemies in Ahimsa Park - abilities grant faster progress
  • Enter Calus’s Typhon Imperator and find the Seed of Silver Wings
  • Return to Nimbus
  • Complete the mission “What Remains”
  • Visit Nimbus again
  • Go to the Hall of Heroes

The whole quest can be completed in a couple of hours. Similar to the Parasite quest in The Witch Queen, you unlock Deterministic Chaos partway through the final “What Remains” mission and get to use it in the final encounter.

Step 3 - Cipher qubits, Cloud Accretions and Rohan’s data


One of the more ambiguous steps in the Unfinished Business quest line is the third, which says: “Collect cipher qubits from the Vex and use them to extract Rohan’s data from Cloud Accretions in Neomuna.” There’s a counter for Cipher qubits, a multiplier for data extractions, and another counter for resources extracted. Huh?

On the surface of it, these instructions make about as much sense as Lightfall’s plot, but beneath the odd wording they are quite straightforward. You just need to shoot a bunch of Vex, who will drop little triangular pickups that give you cipher qubits for as long as this quest step is active. Once your “Data extractions available” multiplier is higher than 5x, you have enough to extract all the data. With 8 qubits per extraction, you need 40 in total.

Then you just need to go around picking up Cloud Accretions, which are Neomuna’s resource nodes. If you’re having trouble finding them, equip a resource-finding mod to your Ghost, which will then signal on your HUD whenever you’re close by to one.

Once you pick up the fifth Cloud Accretion, you should advance to the next step.

Step 6 - Regroup with Nimbus and Osiris in Radiosonde


Where the hell is Radiosonde? It turns out that it’s that place you went to for the campaign mission where you rebooted the CloudArk—remember that one? You enter the big sailboat-style building in the center of Liming Harbor, then work your way up through the interior. You can ignore the Vex or fight them as you go.

Remember that some of the paths through the building involve using vents, while others involve shooting through cracked doorways. If you ever get stuck, just double back and look around for a grill that you can shoot out. Eventually you should find your way to Nimbus and Osiris, who are having an argument about next steps.

Step 8 - Defeat enemies in Ahimsa Park


This seems like an obvious one, but it is worth noting that enemy behavior in the patrol zone sections of Neomuna is a little glitchy at the time of writing, just after launch. For example, it is entirely possible to arrive at Ahimsa Park just after a Terminal Override event has finished—or as it is in the dying stages—and discover the surrounding area does not repopulate with enemies when it concludes. If this happens, just leave the area via one of the paths to Liming Harbor or Strider’s Gate, then come back in and you should find that there are plenty of Cabal wandering around looking for a fight.

It is also worth noting that despite the entrance to one of the new Lost Sectors being located in Ahimsa Park down the side of the Typhon Imperator, killing enemies inside does not count towards your total. You have to do it outside in the Ahimsa Park zone to make progress, but at least you can make slightly faster progress by using your abilities.

Step 9 - Find the Seed of Silver Wings

The next step involves heading inside Calus’s ship, the Typhon Imperator, and looking for a Seed of Silver Wings, but the game’s usually immaculate signposting seems to take the day off for this one, offering only a general waypoint off in the distance, leaving you scrambling around Darkness-imbued hallways not entirely sure that you are going in the right direction.

If you remember back to the early mission in which Osiris sends you hurtling into the Imperator in pursuit of the Radial Mast, you are heading to the final room of that mission again, and your route through the ship should be the same. When you reach the big room where a bridge far below has been disabled, cutting off your advance, look right and there should be an opening in the wall that you can follow. Through there, you need to navigate a few pyramid ship-style rooms with doors located high off the ground. Pretty soon after that, the game gives you a little portal that you can jump through to take you the rest of the way.

Step 11 - Complete the mission “What Remains”


The capstone mission to this exotic quest line is “What Remains”, in which the Guardian returns to the Black Garden to follow in Rohan’s footsteps and look for a way to track down the Witness. On the way you will finally get your hands on Deterministic Chaos, and get a chance to use it.

Players with raid experience will instantly recognize “What Remains” as the Garden of Salvation raid in reverse. Obviously the encounters are different, but the action begins up in the hills near to where raiders once fought the Sanctified Mind, and must work their way backwards through the raid locations before confronting the boss, Conceptual Mind, right back at the raid’s entrance.

It should be fairly straightforward to follow the path through this mission, but there are a couple of snags. The biggest head-scratcher is how to shoot the mini confluxes that are hiding behind immunity shields. If you look closely at your surroundings, you should see mirror-like panels at useful angles nearby. Shoot the nearby Vex Minotaur with the white hue around it, pick up its Arc ray-gun doodad, fire at the mirror and the beam will reflect back and take out the little conflux. This mechanic is used throughout the mission, and eventually you will also do it with rounds from Deterministic Chaos.

How Deterministic Chaos works


With all that said and done, players should get their hands on the Deterministic Chaos exotic heavy machine gun towards the end of “What Remains”, with a few waves of Vex enemies to face afterwards and the Conceptual Mind boss fight.

Deterministic Chaos itself is an interesting weapon. It’s a 360 rpm machine gun, and the Heavy Metal intrinsic trait means that when holding down the trigger, every fourth bullet becomes a heavy projectile that weakens targets on impact. Furthermore, every fourth one of these Heavy Metal bullets will be a Volatile Round. In other words, if you get a target in your sights and hold down the trigger, every 16th shot will be a Volatile Round.

From what we’ve seen so far, it’s an entertaining choice for the power weapon slot, and should synergize well with Void builds. So what are you waiting for? Go get it!