Although it may appear old-fashioned compared to our latest designs, this pistol is remarkably accurate, ensuring that even the most inexperienced of our soldiers will strike their intended targets. There's also a chance they could kill the target and escape undetected. This weapon is unique, and cannot be duplicated or replaced.
The Shadowkeeper is a unique weapon that can be obtained by scanning the Locator Beacon, which also grants the Bolt Caster, Hunter's Axe, and Frost Bomb. It deals identical damage to the Pistol, but it grants the user +10 Aim and +15 Critical Chance on pistol shots.
It also grants a special ability, known as Shadowfall, which, when activated, will fire the pistol on a target with a 100% chance to hit. If Shadowfall kills an enemy, the soldier is immediately granted concealment. Shadowfall has a single charge per mission.
Like all unique weapons and armors in the Alien Hunters DLC, if the soldier the Shadowkeeper is equipped on is killed and not evacuated, the Shadowkeeper will be permanently lost.
Like the other unique weapons save for the Frost Bomb, the Shadowkeeper can be upgraded to integrate magnetic and plasma technology in order to boost its damage output. Each upgrade to the Shadowkeeper will keep its damage on par with the Mag Pistol and Beam Pistol, respectively. The aim and critical chance bonuses, along with the Shadowfall ability, are unaltered by upgrades.
The Enhanced Shadowkeeper requires Magnetic Weapons research in order to construct it, while the Powered Shadowkeeper requires Plasma Rifle research in order to construct it. Both upgrades also require the completion of the Alien Hunters story mission before they can be constructed, as with the other unique weapons.