“Square Enix has promised post-release download content for Final Fantasy XIII-2, but it has yet to provide specific examples. Today, we got some hints as Square Enix announced the download content that will be given to those who buy the game at select shops.
Pre-order FFXIII-2 from Lawsons or HMV, and you’ll get a download code for a weapon for Serah. The weapon is an angel’s bow and arrow that converts the damage it deals to enemies into an HP boost for Serah.
Square Enix promised an image of the item in a future update.”
NOTICE: You may unlock this weapon if you just play the game. Pre-order gift just gives early access to it. *not offcial information*