How to Unlock: “Mysterious Box” exotic quest
1. Find the Mysterious Box location from the Volundr Forge.
2. Open the locks for the hand, a butterfly, a fishhook by completing the Volundr, Izanami and Gofannon Forges with Maximum Temper (by shooting drones mid-battle).
3. Get the Black Armory Key Mold quest from Ada-1.
4. Kill Watchers in the Leviathan Underbelly, then get Glimmering Amethyst from opening Public Event or Strike chests.
5. Clear the Bergusia Forge with Maximum Temper (by shooting drones mid-battle).
6. Complete a rare Black Armory Bounty.
7. Complete the Shattered Throne dungeon.
8. Complete a special version of The Pyramidion Strike.
9. Complete a special version of the Bergusia Forge.
10. Return to Ada-1 to recieve the Izanagi’s Burden.