Halo Wars 2

This achievement can be obtained very quickly in a single match of Solo Blitz Firefight.

To begin, head into Blitz Mode and craft a deck for Commander Jerome, making sure to include the his own hero card, Commander Jerome. The rest of the cards in this deck can vary to whatever suits your desire. Now start a Solo Firefight match, send your starting units to capture at least two of the Control Points, and then recycle the cards in your hand until you draw the Commander Jerome unit. If you have enough energy, summon the him (and his mech) onto the battlefield; if not, hold out on the early waves with your starting units until you can gather enough energy required to call in him in.

With the Jerome and his mech out on the playing field, you can now move the mech around the map, attacking enemies. The mech is extremely powerful and should be able to wipe out units of any kind in just a few seconds. Once you have killed twenty-five enemies with Jerome's Mantis unit, this achievement will unlock.