Quote Originally Posted by Enkidoh View Post
Dissidia NT reboots the Dissidia storyline anyway, given that the original two Disisidia games on the PSP were actually a retroactive pseudo-prequel to FFI despite the appearance of other FF characters (FFI's big villain Chaos was Dissidia's major antagonist, Cid of the Lufaine who was the narrator of Dissidia was (according to the later rereleases of FFI) the original builder of FFI's airship, the world map of Dissidia's world was a ruined lifeless version of FFI's world, and, as WhiteArchmage mentioned above the ending to the original Dissidia dropped off the Warrior of Light directly in front of Corneria Castle, setting up the beginning to the very first FF game).
Just one thing here, the Dissidia story isn't rebooted. All the characters who appeared in the previous two games cleary know each other and the WoL and Lightning talk about Cosmos briefly.

As far as an event goes, it would probably have less to do with the FF heroes and villians and more to do with Materia and Spiritus suddenly appearing or something.