FINAL FANTASY XII THE ZODIAC AGE

This requires you to get 48,000LP across all 6 characters, which comes to an average of 8,000 each. You get at least 1LP per character per enemy you defeat, which comes to at least 6LP for the achievement.

Coming to the end of the game I was on around 70%. After a bit of grinding in the Henne Mines I ended up in the 80s.

I gained the rest by running Trial Mode with speed boost x 4 enabled. So save your game, go into trial mode and speed your way through that to finish off the achievement

I got this achievement right as my characters turned 51. I did get a Golden Armlet pretty early in the game so one character was always earning double LP which probably helped.

If you are working in doing everything else in the game this will come naturally.