The new character, as reported earlier, is named Lumina, and she is described as being a mysterious girl whose unpredictable nature wreaks havoc everywhere she goes. It is undeniable that Lumina looks very similar to Sera, who is Lightning’s sister. Perhaps there is a connection of sorts there.
Besides this tidbit of information, the screenshots show off the city of Luxerion, which is one of the four explorable regions of Nova Chrysalia.
Square Enix is planning on releasing Lightning Returns: Final Fantasy XIII this Fall for the PlayStation 3 and Xbox 360