The Fallow mission for Destiny 2: The Edge of Fate opens up a bit after you have gone deep enough in the Central Academy Strangelet questline. With the Matterspark ability from the Aionian Campus region of Kepler, this mission is purely about using that ability and unlocking Vex secrets deep into an isolated Agricultural Facility. This guide walks you through the combat encounters and puzzles step-by-step and to a multi-phase boss fight.
Getting to the Agricultural Center
First, while doing the Fallow mission, you will be on a train and disembark and go into a small room with a closed door. Behind the door are hostile Vex, but you won’t be able to access them until you acquire the Matterspark skill. To the left of you is the Matterspark module in a corner. When activated, use it to leave the building by way of an open air shaft on the opposite side of the train. This puts you in a outside space where you are able to kill the Vex in the next space.
Keep going down the path until you reach your first large room. There is an Uplifted Choral Minotaur here. Killing this boss opens up a Vex cube. Break the cube to disable the barrier and then move on. Next, take the Matterspark from the top-right corner of the room. Search for an air vent in the middle wall—enter it and move ahead in the tunnel. At the end of the tunnel, destroy a mysterious Vex device to open the door in front. This opens the door to the next section, where you can issue an Aionian command and proceed further into the mission.
Maintaining the Aionian Food Supply
Your second mission is to become a master of the food supply. You are to blow up three Uplifted Choral Minotaurs, each with a distinct cache. Once you take out each of the Minotaurs, you have to fire at a Vex cube floating above them to completely disable defense on the cache. After you take out the cube, walk towards the food storage and send the materials. Once you’ve deposited all three caches and sent them, a Rally Banner point will appear in the middle of the arena, which indicates that a boss fight will start.
Boss Fight: Devastator Mind
The Devastator Mind is the mission boss, a Vex Harpy that deals a whopping three stages of damage. On the first stage, just keep on applying damage until it performs a shield cast. This will make the spawn of an Uplifted Choral Minotaur on the right side of the arena. Kill it to expose and destroy another Vex cube in the area. Then, take the Matterspark located in the middle of the arena.
Go back to where you blew up the cube and fall down through a vent below. There, you will see a second device that you have to blow up to blow up the Devastator Mind shield. That reveals the second damage phase. This is done again: fight the boss until it shields once more, and this time there is a Minotaur that gets unleashed on the left of the room. Kill it, destroy its connected cube, and retrieve Matterspark again.
With Matterspark active, head through the first vent again but this time veer left into a new room. Here, destroy another piece of Vex machinery to disable the final shield and begin the third and final damage phase of the fight. With careful positioning and strong weaponry, you’ll bring the Devastator Mind down.
Finishing the Mission and Unlocking Rosetta II
With the boss defeated, head to the right side of the room. Here, you’ll receive the Rosetta II upgrade, which enhances your ability to decode specific chests and engage with higher-tier puzzles across Kepler. To complete the mission, approach and interact with the nearby terminal. Doing so finalizes the quest and unlocks further mysteries tied to the Aionian tech.
