I can finally explain the ending correctly this time. :)
Some people say XIII’s ending was the result of a Deus Ex Machina, well they’d be correct to a degree.
A character or thing that suddenly enters the story in a novel, play, movie, etc., and solves a problem that had previously seemed impossible to solve.
Except for two small things
1. Etro didn’t do everything during the finale.
2. Etro was briefly alluded to before the journey back to Cocoon but most people miss it because the English of FFXIII was hit with a terrible localization. Here’s the JP version of the cutscene.
Her Providence sought nothing.
Her Providence made nothing.
She but looked on, silent in Her sorrow.
The Goddess pitied mortals, destined as they were to die, and so She deigned to intervene in the hour of their greatest peril.
She averted cataclysm that was to be, and put to rest the ones who would have robbed so many of what time fate had ordained.
Her compassion did not end at this.
The Goddess pitied also those subjected to that fate of Focus, crueler still than death. To them She sent Her messengers, to deliver hope when all was lost.
The goddess sought nothing.
The goddess made nothing.
The goddess only pities.
The goddess pities those destined for death and so she placed those who were to take countless lives to sleep and prevented the destruction.
Even more so than those bound for death, she pities those bound to a cruel mission. To those who become worn by despair and lose sight of their path, she sends her messengers; to guide them towards hope.
1. Hints at Etro’s presence
Those crystal shards represent two things
1. They’re the souls of the dead.
2. They symbolize Etro’s power is at work.
When the game zoomed in here on Etro’s Gate, it mean’t Etro was doing something important like when she reverted Fang’s transformation.
2. The Cie’th thing
It was real and not an illusion that “fal’Cie” smoke and mirrors” crap was said because Light thought that returning to human beings was a trick.
They returned to human form because they combined their strength of Will with Etro’s power. Hence the following
When Lightning says ‘maybe it was more fal’Cie smoke and mirrors’ (ファルシ得意のまやかし as Sazh’s line after seeing Dahj and Serah’s crystals shatter, Lightning says ファルシ好みの幻かもな; both were translated as the same thing in English), it sounds like it might be talking about them turning into Cieth and maybe that wasn’t real. It’s actually about them returning to human form. It’s kind of a joke on Lightning’s part, saying maybe this is just fal’Cie trickery, showing Fang her friends safe and back to normal again to mess with her. (The transformation is definitely real, caused by the shock of what Fang was planning on doing and the critical hit she inflicted on the rest of them.)
That’s not to say that there is absolutely no involvement from the l’Cie. Out of the ‘miracles’ involving Etro (not the false ones from Dysley), there are two types: ones purely down to Etro, and others that occur due to the l’Cie’s strength of will in addition to Etro’s power being involved. The events of Fang’s original transformation fall in the former category, but the ones seen during the final chapter (the l’Cie turning to normal and Fang and Vanille’s Ragnarok saving Cocoon rather than destroying it) are the latter. Etro may have helped, but it was the l’Cie who made it happen.