Square Enix has announced that Dissidia Duodecim Prologus, the weird trademark that appeared a while ago, is nothing more than a paid demo for their upcoming PlayStation Portable title.
It's unclear if the demo will be released in the West, but it's now live in Japan and will cost 300 Yen.
The demo will feature a short scenario, an arcade mode and a few characters. It will also unlock the ability to use Aeris in the full version of the title, but she won't appear in the demo.
Source: Final Fantasy Union