Xirixis, the Unknowable

Xirixis, the Unknowable is a Taken Captain seen in the Lost Souvenir Mission alongside Bab'dotek, the Abhorrent, where the Captain and it's Taken compatriot attempted to intercept The Guardian attempting to recover Ada-1's lost memories of the Black Armory.

Gameplay
After solving the initial puzzle, the two Taken liutenants will appear, protected by an immunity shield. This shield can only be broken by shooting it with Izanagi's Burden. Once one of the two is slain, both will disappear, leaving a Blight behind. Destroying the Blight will make the first slain enemy return as as giant Ultra, again with the special immunity shield. Once the first of the two is slain, the other blight will open, revealing the second Taken as a giant Ultra too. Once the survivor reaches low health, it will summon Shield Drones to protect itself. After destroying the drones, one will have a small window of opportuniy to damage the boss before the drones return. Killing the second boss will cause remaining enemies to leave and open the Black Armory cache.

List of appearances

 * Destiny 2
 * Black Armory