There are multiple Prismatic Fragments you can unlock after you beat the Destiny 2 The Final Shape campaign. Each Prismatic Fragment gives you a new passive to add to your build, providing you with more options for your Guardian, and one of them is the Facet of Command.
Although the Prismatic Chest for the Facet of Command is out in the open, it’s locked. There’s a specific way you have to go about unlocking this chest, and it can be tricky if you don’t know where to go. Unlike many other Prismatic Fragments in Destiny 2, the Facet of Command is a complicated puzzle.
How to get the Divided Prismatic Key in Destiny 2
You can find the Facet of Command Prismatic Chest on your way from The Impasse to The Divide. Head west from The Impress landing zone and go through the highway tunnels. Continue down this path, and roughly halfway through where you encounter the Shrieker, the Prismatic Chest is to the right, out in the open. When you attempt to interact and open the chest, however, it says you need the Divided Prismatic Key. It’s easier to find than the ones you need for the Facet of Dominance.
The way you get this key is by completing a nearby puzzle. Turn around from your position and head through the open windows. These windows hide a transmit station you can interact with, conjuring a Scorch Cannon. Using the Scorch Cannon, find large blocks of ice scattered throughout this underground area.
These drop elemental charges, and if you bring the charges to the transformers next to the Transmat station, it charges them up. You can’t just do them in any order you want, though. They need to be in a specific order. You need to reach 10 charges but not exceed this amount. Arc Charges equal two, Solar Charges are worth three, and Void charges are four. I typically had two Void charges go into one with a single Arc Charge and then two Solar with two Arc charges
From here, multiple enemies spawn outside the area where you can find the Prismatic Chest. Defeat them, and a Subjugator boss appears at the end. Upon defeating them and the rest of the enemies, you earn the Divided Prismatic Key, allowing you to open the chest and earn the Facet of Command.