XCOM 2

Story-related and cannot be missed.

To recover a Codex brain, you must find build the Proving Ground (see Tinker) and research the Skulljack. Next, you must equip the Skulljack on one of your soldiers (preferably a Specialist, as they benefit the most) and find an ADVENT Officer. They are a relatively common enemy. If you have the Shadow Chamber, you can check the Geoscape to see what enemies are present in a mission. Once you locate an ADVENT Officer, you simply need to use the Skulljack on him (With Extreme Prejudice will pop). Make sure to kill any enemy units around him first, though, as your soldier will likely not be in cover after using the Skulljack, and you want to be prepared for what happens next.

If the Skulljack connects, the officer will be killed and the single most annoying enemy in the game (a Codex) will appear. While the Codex is relatively weak, it can teleport (bypassing Overwatch and flanking your troops), cast an area-of-effect attack called Psionic Rift that empties the ammo of any gun in its range (and explodes on the next turn, damaging any units still in range) and it automatically creates a clone of itself if it takes any damage that does not outright kill it (and those clones can make additional clones if they are attacked and so on). Fortunately, the original Codex and its clone will split their remaining health so they become progressively easier to kill but they are still arguably the most dangerous unit in the game.

There are a few ways to deal with a Codex. One option is to use a Flashbang Grenade or any weapon that disorients a target, as this will prevent the Codex from cloning. A second option is to fire a ranger’s shotgun at point-blank range and pray you get a critical hit. A third option is simply to keep attacking until the Codex and its clones until all are dead. If there are no other enemies on the map to worry about, this isn’t so bad. The problem, is that the clone always appears in a random location on the map and it is possible that none of your soldiers will have a direct line of sight. If you have consumables, such as grenades, then this is a great time to use them.

This trophy will pop once you have successfully summoned and killed your first Codex. There is a chance that your Skulljack can fail so you may want to create a manual save right before using it. Note: You can use the Skulljack once per mission so you can always try again on a later mission if you fail and forget or don’t want to load an earlier save. The Skulljack is actually a great item to use because it can kill ADVENT soldiers instantly, regardless of their health and it has a decent success rate. Also a Codex won’t appear the next time you use it so Skulljack away!