Great Old One
Okay so nobody else made the thread and I got the honor I'm gonna cut and paste from the updates of various people in the XIII-2 thread and the 25th Anniversary event thing thread:
Hito makes a good point on the name:
the logo is "lightning returns: final fantasy xiii", and they took that direction (reversing the order of the title) with the compilation of ffvii (dirge of cerberus/crisis core/before crisis: final fantasy vii)? i don't see why it would change
This image I found on this unofficial FB page:
Think that's just concept art, but still. (Edit: It's from here, it's a painting?) She shows up in more of the concept art which can be seen on that Facebook page.
A trailer was screened on the event, but filming and photos was prohibited. Sure someone did film it, we'll just have to wait and see Though I guess it's worth waiting for the quality one from SE.