I mean, the fact the Cetra could "unlock" the planet, speak to the planet, and read the planet were the reasons why the Shinra Company made it priority 1 to capture Ifalna and Aerith for their plans to create "Neo-Midgar" and find more abundant sites of mako to increase their profits.
It's why Shinra funded Bugenhagen's research and Dr. Gast's research in understanding The Ancients and just what exactly Jenova was.
There was a very real, and profit driven motive for having the power of the Cetra on their side.
And if you want an glimpse of how those powers of the Cetra could be utilized... I only bring up FFX because of it's intentional thematic parallel.
The Guado were the race on Spira who were closest to the Farplane and truly understood Spira's pyreflies. They were able to read, manipulate (this is clearly seen when Seymour's henchmen and Seymour himself would mold pyreflies into fiends to attack Yuna and co.) and protect the spirit energy of the Farplane. When the Guado lost standing amongst Spira due to supporting the mad machinations of Seymour Guado, they were driven from Guadosalam and cut off from watching and protecting the Farplane.
And it was around this time when the Farplane became unstable.
The Guado and Cetra were both people who were capable of sensing the dead, and communicating with them. Aerith was able to see Elmyra's dead husband and hear the cries of dead souls from the Lifestream. The Guado were able to sense and smell the dead as Unsent. Numerous times, the Cetra and the Guado were capable of using their abilities to communicate with the spirit energy of the planet.
And the Cetra and Guado were capable of communicating with the living from beyond the grave as well.
Jyscal Guado manifested himself as a spirit from the Farplane and even created a convenient sphere to tell the whole truth of who murdered him!
The long dead guardians of the Temple of The Ancients remained within said temple to stay behind and guard its rooms, to the point they lost their abilities to speak, and everything else mortals take for granted. They were Unsent, in a manner of speaking.
And of course...Aerith herself was able to maintain her consciousness after death death, rally the Lifestream to help Holy stop Meteor,
leave fucking voicemails from beyond the grave on Cloud's cell phone, talk to Cloud and Marlene from beyond, and finally cure an incurable disease inflicted by Sephiroth upon the population of Gaia. This is of course not even counting the unexplained sightings of Aerith by children that would happen at her church during FFVII, and of course the sighting of her that would occur right in front of the player.
And you know who else was able to do so many
marvelous things despite being dead?
Seymour Guado.
Aerith, for all intents and purposes, was a benevolent, Psuedo-Unsent. She can screw the planetary rules of death and recycling by willpower alone. Not to the extent of Sephiroth but
very close. Because of her Cetra existence.
There are some very striking and obvious parallels between the Guado and Cetra. I don't think it's coincidence. The Guado are probably the closest hint at what the Cetra might have done or been like on Gaia before they were nearly wiped out by Jenova's arrival on the planet.
No, I don't mean that the Guado are descendants of the Cetra or anything like that. But they're similar.
Very similar.
