History of D.A.R.C.I.

D.A.R.C.I. (Data Analysis, Reconnaissance, and Cooperative Intelligence) is an Arc Exotic Sniper Rifle that has been in the game since Season 1.

Overview

• Archetype: Sniper Rifle (Arc), high stability and handling, slower reload than rivals such as Whisper of the Worm.
• Intrinsic perk: "Personal Assistant". Aiming at an enemy shows its health, shield, distance and power level in the scope.
• Fixed perks include Extended Barrel, Extended Mag, Short-Action Stock and Target Acquired.

Acquisition

• Extremely rare world drop from any enemy; Exotic Engram drops can also give it.
• Sold occasionally by Xûr (Exotic Engrams for Legendary Shards), per the Destiny 2 Wiki and ScreenRant.
• Can be recovered from the Exotic Kiosk once owned.

Catalyst

Drops randomly from non-Guardian enemies anywhere. Complete it with 300 precision kills (kills before the drop count retroactively). Sources disagree on the stat bonus: the Destiny 2 Wiki and GameRant's catalyst article give +18 stability, while an older GameRant summary and a later update mention +20 and a "Networked Targeting" perk (nearby allies' non-Exotic weapons gain performance and precision damage), which appears to be a newer version of the catalyst.