
Originally Posted by
Toranja
She took the wrong turn in the Historia Crux.
(I'll be surprised if this isn't the answer.)
Well, the Historia Crux only connected various time periods in FFXIII's world, not XIV. However, I'm liable to believe SE has used her storyline in Dissida Duodecium 012 to explain her appearance in Hydaelyn -
the last the player saw of her in Dissida 012 was she disappeared along with Tifa, Kain, Laguna, Yuna and Vaan after being overcome by the manikins while trying to seal the rift into the Void - they were not 'reborn' as part of the usual cycle of war in Dissidia so other than 'fading away' (ala, permadeath), whose to say she was cast into the Void, eventually ending up in Hydaelyn due to the Calamity weakening the boundaries between dimensions?
The fact that when she shows up during the event FATE she mentions about being 'trapped' in a 'ceaseless cycle of war' seems to lend weight to a Dissidia link (not to mention her reference to 'sleeping' could be metaphorical for that above scene in the spoiler I posted above). Or else she's just referring to XIII-2 and the endless cycle of war in Valhalla. Either way, I guess we'll find out soon when the rest of the quest chapters begin.