Age of Wonders: Planetfall (PC) - Achievement - Line 'em up!
Use a Shakarn Deadeye to hit 3 units by using a single ability
A simple way to obtain this achievement is to use your own troops as the target. The achievement doesn't specify it needs to be enemies. This also makes it easier to make sure there are 3 units lined up. Simply arrange 3 friendly units in a line in a manual battle, then use a Shakarn Deadeye to use the 'Omni-Perforator' ability on them.