XCOM 2

achievement is directly related to the main story, it requires researching biotech to complete advent officer autopsy, which will allow you to build a shadow chamber. after it’s completed, start the skulljack project. the skulljack allows you to use the “skulljack” ability on officers within dash/melee range, it also gives the equipped soldier +25 to hack, excellent for specialists. i’ve always used them on rangers until learning about the boosted hack skill. once you’ve entered a mission and found a group of advent including a officer, be sure to either quickly dispatch any other enemies close enough to cause issue or sneakily dash a trooper to skulljack. it’s roughly a 70ish, if not more, chance of hitting. you will then open up the hacking screen. go for the first option as they will have higher chances of success. jacked enemies die after success, or take two damage after failure. be sure to be well prepared as once jacked, a codex will spawn. killing the codex and finishing mission will also get you the achievement “A Grim Key” for recovering the codex brain.