Defeated a powerful enemy with perfect execution.
This is story-related and can only be done in Academia 500AF (Episode 6).
You will run into this bossfight automatically, there is no way to miss it. It's highly recommended to set the difficulty down to easy when you want to get the trophy / achievement without having maxed out characters. As always, attack with Ravagers to stagger your enemies and switch to a Commando Paradigm to cause heavy damage. The only thing that makes this fight a little more tricky is the fact that the enemies respawn if you don't take them out at about the same time. Best strategy is to bring down the health of one enemy until it's nearly dead (but don't kill it yet) and switch to its companion. You can come back here at any time via time reversal and try again if you couldn't meet the requirements the first time. You might want to level up some more if you experience problems.