Shinryu

I know there is a Shinryu in Final Fantasy X which was a dragon like creature that could be fought underwater.

Not sure if Shinryu will make an appearance though.

Shinryu plays a MAJOR part in Dissidia. He, along with Cid of the Lufaine from the original Final Fantasy, are the ones who started this endless war. Though I've explain this several times within both Dissidia forums, Cid and his wife were the foster parents of Garland. Cid was a scientist studying the effects of Harmony and Discord. Garland is the result of Cid being commissioned by the Lufenian military to create a weapon strong enough to defeat Omega, who was summoned by a neighboring nation to destroy Lufenia.

However, when the time came, Garland was taken by the military when that nation attacked. When Garland refused to respond, his foster mother was forced to make Garland aid them, and as such, Garland slaughtered both soldiers and civilians alike. When Cid's wife refused to go on any more missions after what she saw Garland do, she and Cid were imprisoned and the Lufenian army took Cid's research on Harmony in order to control Garland.

The two managed to escape, however, using monsters as decoys, and found Garland in a laboratory, weak from war, and staring at a clone of his foster mother (this clone is thought to be Cosmos, as Chaos has a dream of him and her being happy together). Cid's wife explained what had happened, and Garland agrees to flee Lufenia with them. Using his powers of Discord, Garland opens a portal to the Interdimensional Rift, however, Cid's wife is shot before she could enter. Cid and Garland escape, while Cid's wife returns to Lufenia, right before Cid's Levistone made the city lift into the air creating the Flying Fortress. She records her memories using a ritual for future generations.

Now, on to Shinryu...

What happens to Cid and Garland is unknown, however, Cid meets Shinryu in the Interdimensional Rift, and the two make a deal. Cid loses his body, and Shinryu would create a world with an endless war. Two gods would watch over this war: Chaos and Cosmos. Each time the war is over, the combatants and the god that died who be revived, and the war would start over.

Cid believed that by continuing this cycle, he would learn the ultimate power behind Harmony and Discord. But, after he and Shinryu managed to make his research a success, the two work to end the war and stop the cycle they caused.

Which is why I said that the 3rd Dissidia is likely the last, since the secret ending of the first Dissidia outlined Cid saying that he was going to end the war. This game could have actually been the end of Dissidia, but it's a prequel. Which I'm happy about. XD

As to what Shinryu IS, he's an enormous dragon.

I'd say they could have if they started with the 1st war, but because of the original Dissidia being the 13th war in celebration of FFXIII, they skipped several games worth and at the end of the original Dissidia Cid said he was going to attempt to close the open rifts and set the universe right.

I would actually like to see some power try to use the problems Cid caused for their own use, but I would want the the game not to be an "arcade fighter" type, which restricts the story and game execution.

It's not my word that says it's possibly the last game, it's Squares in game words. But like to say, since Dissidia was successful, and a remade version is in Duodecim, they could retcon it.

I never paid the plot any ounce of attention in the first.

This is great!!! I have Shinryu as a Summon now!! After i bet Feral Chaos, each time i went to go choose a summon, i would see the one with no name on it! I chose it and when i activate it... its Shinryu Versus!!! I was like OMFG!! My game is probably different then the others because my friends has the game i have and when he beat Feral Chaos he dosent have SHinryu's Summon. Anyway i can also use Shinryu as a summon on the rest of the characters but they have to be lvl 100 but f*** that, im usin Feral Chaos because regardless of his level, i can summon Shinryu!!! All bow down before me, as i will own that game!!!

Shinyru is rigged everytime you fight Chaos at 100 or 120. It's ridiculous.