Lost Odyssey

Over the course of the game, your characters gain experience. When you get the White Boa on Disc 4, there is an area called the Temple Of Enlightenment, a very challenging dungeon. In the beginning of this dungeon is a save point. save there, and run in circles with Jensen and the 4 immortals in your party (Kaim & Seth in front, the other 2 immortals in the back, along with Jansen). The enemies will be hard if your around level 40, but once you hit 50 they get very easy. You will gain 1 level per battle up to around level 60, then only certain enemies you face will level you per battle. Eventually, only the Hellish Kelolons will level you per battle and they are pretty rare. But, you will have this achievement long before this happens.

To get all of his skills, you must level him up to level 52. Two good places to do this are the Secret Cave (early in disk 4) and the Temple of Enlightenment (later in disk 4).