~You defeated 3 enemies in one battle while your buddy was knocked out.~

Chances are that this trophy will come naturally. However, it's recommended to earn this AFTER you complet the game because it will lock you out of the No Child Left Behind trophy.

All you have to do is get into a fight with more than 3 enemies and defeat them AFTER your party member is knocked down. A great place to earn this would be in the Lost Forest since wolves howl for backup. Have Jimmy as your companion since he's very vulnerable to physical damage. Once in battle, have Jimmy attack with his crossbow without pressing SQUARE at the flash to reduce damage to the enemy. Do this with Douchebag as well until Jimmy is knocked out. Once he is knocked out, defeat the enemies and the trophy will unlock. It must be three however.