Use this to fill up someone's XP meter (Including your own.) All that happens when you level it up is that the AP cost goes down. Regardless of the level, the target's XP meter will be completely full after using it. Useful if the target uses combos a lot. Get as a pre-requisite for Masquerade. Little need to actually max it. Can be very useful to combo jesters since you won't need to take a long time refilling your XP.