Speaking with Dengeki PlayStation Tetsuya Nomura said they still have more Dissidia 012[duodecim]: Final Fantasy to reveal. While he didn’t give any hints, he said the characters would be from "Super Famicom and there after."
Total speculation, but I’m betting on Gilgamesh from Final Fantasy V for the Chaos side. The forces of evil need some help – big time.
Nomura also said it will take around 60 hours to clear the game and there will be some sort of Dissidia 012[duodecim]: Final Fantasy surprise at the January press conference. Dengeki also described the limited edition PSP announced at Jump Festa. It’s two-toned. Pearl white on top and matte black on the bottom with an illustration from Yoshitaka Amano.
Dissida 012[duodecim]: Final Fantasy is set for a March 3 release in Japan and spring in the West.