WARNING: This code can be hazardous to your characters' health if they're too weak.

Take on the Silver Soldier mission after returning to Motavia, follow the directions, and go north of the Plate System to an island. The fort here has easy foes with 2000+ exp. each. Kill off all but Wren(and any other *character* you want to build fast and fight as much as possible. You can get 10,000-20,000 exp. a battle.

NOTE: This trick will *NOT* be an option if you don't take the Silver Soldier mission before getting the Elsydeon.