A recent issue of the Japanese Shonen Jump magazine has revealed that Yuna from Final Fantasy X and X-2 will be joining the cast of Dissidia Duodecim: Final Fantasy. It may be surprising for some, but Yuna will appear in the game as she was in Final Fantasy X, rather than as she did in the sequel. As such, she will function in the game as a summoner rather than as a gunner with a class change system.
According to Shonen Jump, Yuna will fight by summoning out Aeons to attack for her. She can summon out two Aeons at once who can attack as a team. One known example is attacking with both Ixion and Shiva at the same time. Her EX Burst attack involves summoning all of her Aeons to attack in succession.
In addition to announcing Yuna, the magazine also revealed information about a promotion Square Enix is running for the initial run of the game. Every copy of Dissidia Duodecim's initial Japanese print run will include a code for downloading a new costume for Tifa to use in the game, which will be a modified version of her Final Fantasy VII costume with a red skirt. It is still unknown whether this promotional code will be included in the North American release of the game.