Square Enix will release its promised Lightning-focused DLC for Final Fantasy 13-2 at some point in May 2012, according to a report from Dengeki PlayStation (via Andriasang). The assumption is that the new content will come sometime after the planned May 15 release of the Snow-focused DLC pack.
The Lightning DLC, called Requiem of the Goddess, involves a battle between Serah's older sister and Caius, the FF13-2 antagonist. Finish the DLC and you'll unlock Armored Lightning for use as a party member, complete with her own set of abilities. Also coming in May is another content pack that will add White Mage Serah and Black Mage Noel costumes, along with 16 Moogle costumes, to the game.