Magnum Opus

A strange treasure awaits you once you have proved your loyalty to Xûr by raising your reputation.

Details
Start point	Collect Strange Coins and bring them back to Starhorse in Eternity.
Requirements	Bungie 30th Anniversary Pack Dares of Eternity Activity obtained fromEternity Beckons Quest 30th Anniversary Pack To the Daring Go the Spoils Quest Dares of Eternity Activity obtained fromEternity Beckons Quest 30th Anniversary Pack Xûr obtained fromTo the Daring Go the Spoils Quest Dares of Eternity Activity obtained fromEternity Beckons Quest 30th Anniversary Pack Xûr
Rewards	Forerunner Magnum Opus II
Required for	Anomalous Object, Forerunner, Magnum Opus II, Strange Key, What Came Before

Magnum Opus is the Exotic quest for the Forerunner Sidearm, started from Xûr in Eternity and tied to Dares of Eternity and the Bungie 30th Anniversary Pack (introduced December 2021). Expect many hours of reputation grinding.

Reports differ on ownership requirements: some say the Bungie 30th Anniversary Pack is needed, while others say Forerunner is free to all players.

Collect 7 Strange Coins (from Dares of Eternity, Strikes, Gambit, Crucible, Public Events, or bounties) and bring them to Starhorse in Eternity.
Obtain and complete 3 Starhorse bounties (one at a time, bought with Strange Coins; harder ones give bonus progress).
Reach Strange Favor rank "Brave" and take the Strange Key from Xûr.
Return to Eternity and speak to Xûr.
Use the Strange Key: leave Xûr's Treasure Hoard, step into the purple smoke to reach the Valley, find the stone in the rocks, then complete the jumping puzzle in the cave (floating spheres, shifting blocks) to reach the Anomalous Object in a cryo pod.
Bring the Anomalous Object to Banshee-44 in the Tower.

Quest steps (from game data)