This is the final stage of the previous two trophies:
This time, an extra hundred fights are pinned to the last trophy, but the same idea is that you will want to actually grind out some fights early on, at least during your first playthrough. If anything, it helps to explore the areas for items by depleting the Encounter Bar as soon as possible, because once it's empty, you will only refill it by zoning out! It's a win/win!