Dissidia 012 Final Fantasy Gets Premium Demo, Two New Fighters - gamrFeed
Dissidia Duodecim Final Fantasy was featured at Square-Enix's press event, which focused mainly on Fabula Nova Crystallis, but held some information for other titles as well.

Here, they confirmed that the game has a demo available today, entitled Dissidia 012 Prologus. A premium demo, bigger than a normal demo, and it costs 300 yen. They also said that if you buy Prologus, you'll have access to Aerith as a support character in the full game later.

They also mentioned that Yuna's original japanese voice actress, Mayuko Aoki, will be returning.

Takahashi Mitsunori, the director of the game, went on record saying that they would add “as many characters as they can” before the game's March release date, and went on to reveal two new characters right off the bat - Gilgamesh from Final Fantasy V and Prishe from Final Fantasy XI.

The entire current roster of newcomers in Dissidia Duodecim Final Fantasy are listed below, with the ones revealed right now bolded:

Kain Highwind (Final Fantasy IV)
Gilgamesh (Final Fantasy V)
Tifa Lockhart (Final Fantasy VII)
Laguna Loire (Final Fantasy VIII)
Yuna (Final Fantasy X)
Prishe (Final Fantasy XI)
Vaan (Final Fantasy XII)
Lightning (Final Fantasy XIII)