Infel won that war. It wasn't exactly a cheap victory, given that all the fatalities were on her side, but she won. Unfortunately for her, the thing she wanted from Frelia was simply outside Frelia's ability to give; if she'd had enough power to create land then they wouldn't be in this mess in the first place. Frelia was never the bogeyman she was painted as, but Frelia also lacked agency for almost her entire life.
It goes somewhat like this, chronologically; the pre-tower parts of this are a little uncertain:
- Sol Cluster and Sol Ciel are in a state of war. This is pre-apocalypse, and indeed pre-Reyvateil.
- Sound Science is developed by some very smart people in Sol Ciel. They decide to create Ar Tonelico, which is intended as a weapon of war. Simultaneously, the Reyvateil project is completed, with the creation of the first Reyvateil, Eoria. The Reyvateils are a joint military-civilian project; the civilian side intended it as the Next-Generation Human project, while the military of course wanted soldiers. So what they got was the NGH AGI system combined with a military-developed chassis. Suffice to say, Reyvateils were never deployed in that particular conflict. They were used later, but they aren't very good soldiers; they're too nice, so if your opponent isn't a monster your generals will be in trouble.
- Probably as a side effect of being derived from the NGH project, the Reyvateil AGI system is compatible with human uploads, and will over time extend and convert a human upload into a normal Reyvateil. This is never explicitly stated, but is implicit in every bit of the story's treatment of third-generations.
- At about this time Hymmnos is developed, with Central Standard Note being the human-level programming language for Ar Tonelico. An understanding of it is also built into Reyvateils; as Einsig pointed out, it isn't really optimised for being used by AIs, and the original military package included expert systems that allow humans to use it reasonably well. Mind you, this still means that Reyvateils can make a song in a couple minutes that a human would spend weeks or months to encode.
- Some time before this all happens, one of the lead Sound Science researchers--Eleno--loses his daughter, who is caught up in a bomb from Sol Cluster that got through security. Yes, this is the sort of war that includes terrorist-like tactics. The two areas do not like each other. As a result of the trauma from this event, he ends up adopting Eoria, seeing in her someone very like his daughter. (This is not an official adoption, but he manages to place himself in the lead on the team managing her such that the effect is the same.)
His daughter's name was Shurelia, and he reuses it for Eoria.
Shurelia is well aware of her original name, but never uses it. It's pretty clear that he was an immense influence on her. Note that the three Origins' names--Eoria, Frelia and Tyria--are based on three goddesses in Ar Ciel legend. (Which may, possibly be the corrupted names of some of the Ciel nosurge protagonists, or even combinations.)
And now we get to the meat of this.
- Ar Tonelico itself does not have the range to reach Sol Cluster. It gives Sol Ciel unparalled military control of its surrounding area, but can't end the conflict. To do so, they design a relay satellite--something similar to Sasha's Kaira, only it's much bigger, more capable, and intended as a permanent installation. They call it Sol=Marta, and it would extend the range of Ar Tonelico's weaponry to cover Sol Cluster as a whole.
- Metafalls is at this point a satellite nation of Sol Ciel; somewhat like, say, Mexico is to the USA, though details are scarce. What is known is that their land is mostly desert. As payment for being allowed to permanently station Sol=Marta over them, they promise to use their new scientific knowhow[1] to create Metafalica, the green land promised in their legends. (There is an actual green land nearby, mind you. It's called Sol Ciel.)
- Frelia is created, and the Sol Marta design extended to include a song server for her use. Sol Marta does not in fact include a song server for Beta-class Reyvateils (or 3rd-generations, although those were not intended); the non-IPD Reyvateils on Metafalls do connect to Sol Marta, but the connection is proxied through to Ar Tonelico. For most purposes this makes no difference.
Frelia is also the testbed for the Beta-class Reyvateil mind design, specifically D-Cellophane. D-Cellophane improves on the HD-Cellophane that Shurelia uses in one important respect: It's read-write instead of read-only. As either type of Cellophane specifies the overall physical and mental layout of the Reyvateil, this means that Betas have fewer limits than Origins. However, this is also one of the reason why the Beta lifespan is sadly limited, at a mere 150 years; the original design called for Reyvateils to be unaging. That is, however, only a problem without maintenance, and one they fully expect to solve in the future; in fact, probably before the first one even hits fifty. And it's not like there'll be an apocalypse, right?
It's hard to say whether or not the mutability of Frelia's mind means it has an expiration date, since she spent a lot of time in suspended animation, but it's certainly true that she took following events much harder than Shurelia or Tyria. The latter two basically can't be traumatized.
D-Cellophane also adds one staple of the series: The "Cosmosphere" mind-debugging interface. HD-Cellophane does not have it. So, Shurelia and Tyria do not have cosmospheres, while Frelia has one--it simply doesn't show up in-game.
So, Frelia was not important for Sol Ciel's ambitions in the area. She's there as payment; she was in fact delivered to Metafalls shortly after creation, and grew up there for several years before Sol Marta was completed. One of her best friends there was a boy who, surprisingly, is still alive--though he got uploaded at some point and now has a giant blue wolf for a body.
(Well, he'd say that he isn't quite the same person. Frelia clearly believes otherwise. I'm happy she's got that, at least...)
As a result, Frelia does not control Sol=Marta's functions, though she has priority access to its power input. She also does not control its defensive AI, Raki, which is what actually ran the war against Infel. Raki's only priority is to maintain Sol Marta's existence, and Infel was risking that; she doesn't appear terribly concerned about Frelia herself. Raki is also not a Reyvateil, but rather a Sol Ciel military AI.
What happened to cause AT2 is this:
- Grathnode Inferia. As Sol Marta was nearing operation, a Teru bombing destroyed the power regulator circuits in Ar Tonelico, which caused it go haywire and pretty much finish off the planet.
- Frelia was at that point busy creating what we now know as Metafalls, with quite a lot of help. She had not quite completed the, well, humongous sound science-based 3D printer that would actually create Metafalica; that printer is what everyone now lives on. Naturally, it is not terribly hospitable.
- Because of the damage to Ar Tonelico, the power flow to Sol Marta nearly cut off, leaving Frelia unable to finish the job.
- Lots of stuff happened. For the next few hundred years, everyone was too busy just surviving to worry about wars, and the countries lost contact. At some point Shurelia was (deliberately) damaged, causing her to lose her memory that Metafalls even existed; after that, she was too busy suppressing Mir (who'd risen in rebellion specifically to rescue Shurelia) to really do much else. You can see why Mir might be a little bitter, although it all worked out in the end. Mir was, not to put too fine a point on it, younger than Hana at the time. She was also provoked to a point that'd send any human into a berserker rage. Reyvateils aren't really supposed to do that, but.. yeah. There are limits, and she's a Neo-Beta; they'd messed (badly) with her emotional controls.
- Infel and Nenesha were born. At the time, Metafalls had achieved a better understanding of sound science than Sol Ciel had at the time of Inferia, and Infel--a genius even among Reyvateils--promptly put this to use designing Infel Phira, which would work around the power limitations by extracting power from every IPD connected to it. This was also helped by their theory of the Heart of Gaia, which would make the created land largely self-sustaining once completed; thus, they could keep expanding as necessary. Unfortunately, although she'd originally hoped otherwise, it turned out that the procedure for making a heart was too complex for even a Reyvateil to manage, but...
Well, Infel was an absolute genius, and she managed to work around it with Metafalica Mode, which allows every IPD connected to Infel Phira to contribute to the process.
Unfortunately, this requires them all to agree about what they're doing.
You can probably see where this is going. Infel and Nenesha assumed too much about the people they were leading, and failed to account for human weakness; Reyvateils, while generally nice, aren't absolutely perfect. The IPDs, while Metafalica was running, saw that Infel was doing it more for the sake of fulfilling Nenesha's dream than for them. And while under normal circumstances you'd shrug and go "Yeah, but she's also doing it for everyone else, and the result is the same"... a short moment of doubt, multiplied by a thousand IPDs, was enough to ruin the stability of the power flow.
Nenesha attempted to backstop by taking power from Frelia, which she could do due to having Frelia's hymn code. As Frelia had no spare power to give--having bled herself white keeping as much of Metafalls working and non-collapsed as possible--this mostly succeeded in draining Sol Marta of the power it needed to stay afloat[2], and torturing Frelia--upon which Raki, concerned about the first half of that, descended to Metafalls and killed Nenesha.
This happened while parts of Metafalls were collapsing, because Nenesha, again, was depriving Frelia of the power she needed to keep it afloat.
Infel, who did not know any of this, basically went mad with rage and grief, and declared war on the goddess, proclaiming that if Frelia was going to stop them from creating land with such harsh measures then she was going to take the power she needed. Raki was forced to retreat, but came back with the Divine Army (of robots), Infel Phira was seriously damaged, hundreds of IPDs died... and Infel won the war.
But, since what she wanted was physically impossible, they instead came up with the plan for Hibernation. This involved reformatting Infel Phira, uploading the entire population of Metafalls to it (sans the IPDs, who'd be dead), and putting Frelia in suspended animation to join them. Only the last part of that actually happened. I don't recall if it was ever stated why, but "All the IPDs would die" was likely part of it; Infel by that point may have been suicidal, but the rest of them certainly weren't.
Then, midway through AT2, Infel's ghost[3] showed up and attempted to resume the process.
So, when Cloche attempts to attack Sol Marta with Replekia and Luca goes "Stop! Don't destroy this world!"...
Luca's side of it is absolutely, one hundred percent correct. Up until the point they try to go through with Hibernation, anyway. Infel certainly wasn't expecting Leyka and Luca to succeed in singing Metafalica, when she failed herself.
It's quite the demonstration of Cloche's personality and skills that they do, and a side of her that I honestly think wasn't represented well enough in-game, though I'd have been hard pressed to do half as well myself.
1: And near-infinite power feed, courtesy of... one of Eleno's birthday presents to the original Shurelia, wtf... suspecting Earth shenanigans here...
2: Sol Marta isn't on the equator. It's in a geostationary, powered orbit at a middling latitude. Yeah...
3: ..upload, whichever; it's really no surprise that someone capable of building a song server would be able to escape her body's death, seeing as Reyvateil minds don't depend on their bodies in any real way at all; it's, um, a malfunctioning garbage-collection system or something that makes them actually die. It's more interesting that Nenesha also lived.
