Completing the Destiny 2: Lightfall campaign unlocks additional quests for new Exotic weapons, and one of those quests is called Unfinished Business, which rewards the Deterministic Chaos Void machine gun. A heavy projectile weakens targets on impact every fourth bullet and every 16th bullet makes enemies volatile when holding down the trigger. To start the Unfinished Business Exotic quest, speak with Nimbus after completing the Lightfall campaign. Here's everything you need to know about the quest, including how to find Cipher Qubits and Cloud Accretions.

Unfinished Business quest

The first task has you visit the Hall of Heroes, which is a few steps above the Strider’s Gate landing zone, then talk with Nimbus again after the cutscene. (While at the Hall of Heroes, you should speak to the hologram of city archivist Quinn Laghari to get a quest called Welcome to the Hall of Heroes that leads to the Winterbite Exotic weapon quest.)

The third step asks you to collect Cipher Qubits that drop from defeated Vex and extract five resources. These resources are shiny crystal shards called Cloud Accretion that are basically Neomuna’s destination material--adding the resource detector mod on your Ghost helps find them. You’ll need eight Cipher Qubits to extract Rohan’s data from each Cloud Accretion.