Destiny 2 has laid out the Magnum Opus quest and though it is not hard, step 5 is proving troublesome. This is because it is not very clear where one item, the Strange Key, should be used. The purpose of the key is to unlock a cave. Within it, you can find an Anomalous Object which you can swap for the Forerunner Firearm. Read on as we discuss how to complete step 5 in Destiny 2 Magnum Opus.
Once you have the Strange Key in your grasp, you need to head to Eternity. The key can unlock Xur’s Treasure Hoard. From the spawn location, you need to turn right, travel to the opposite side, and go through the portal. In front of you will be a pathway, a large, paved circle, and cliff faces to either side.
On the right of the circle, there is a pile of rocks, which you can see in the above image. The key will work on this pile of innocent-looking stones. Unlocking requires you to stand almost on top of the rock, so you need to get close. Once you have done this, go opposite to the other side of the circle, past the ice, and to the cliff face. A cave will have opened up that you can enter.
The cave contains a small puzzle that makes you do some platforming. Once you reach the top of the cave you enter an opening. In it lays a cryopod. Once you interact with it you will get hold of an Anomalous Object.
Once you have this, travel back to the Tower, and give the object to Banshee. He tells you that he can fix the object and gives you a gift in return. This is the Forerunner Sidearm. Our video guide can help you if you still need some visual clues.
If you need further help with Destiny 2 Shadowkeep, check out our guides on Dead Ghost Locations, Jade Rabbit Locations, and Eyes on the Moon - How to Start Vex Invasion. If it's Exotic Weapons that you're after, we've got you covered with our Pain And Gain Exotic Quest and Deathbringer Exotic Rocket Launcher - Symphony of Death guides. Going back in time for new players, we can offer you guides like Ikelos Weapons - How to Get SMG, Sniper Rifle, Shotgun, or, if you're playing Forsaken content, guides like Corsair Down & Badge - Dead Body Locations.