It's probably fake but then again, Hiroyuki Itou (FFXII's director) hasn't been working on anything significant since FFXII International. It's possibly a leak from a planned press confernece that was to be held in the coming months or at E3. Still, the plot hits too many elements of the Ivalice storyline, it basically sounds too good to be true because the story sounds like it would tie up all the connections between XII, Tactics, and Vagrant Story. So that's where I find it really implausible to be real. It sounds like a juicy fanfiction story by an avid Ivalice fan.