XCOM 2

Templars begin with a maximum focus of 2. It can be raised to 3 with the captain-rank Deep Focus ability, but you do not have to do this for the achievement. The achievement can be unlocked by raising your Templar hero's focus to 2, then spending both focus points, then earning 2 more again. You can do this at squaddie rank by getting 2 Rend kills, then using your Volt attack twice, then getting 2 Rend kills. There are, of course, more elaborate ways of doing it as your Templar hero ranks up and unlocks more abilities, but it isn't hard at all to get it at squaddie.