Finally back to the Light Wing, Azel, the Divine Visitor… and thus what I think the rest of this actually means for solving the core puzzles of the whole story.
I mentioned Sestren’s dragon form being original, I’m not sure how important that may be to much else yet, but it is good to have an accurate understanding on principle; which I didn’t for a long time. The second clear derailment for my own earliest impressions was from a single literal lie we are told, by Zadoc: when he gives us the Book of Skiad Ops Endow, he also says it was written by the “last dragon rider”. I understood Zwei to be a prequel, so for a long time I thought Endow was Kyle, because at that time I’d never known his name either. Of course it’s clear from the last few pages that it can only be Lundi, but at first the technicality got jumbled in the general information stream for me. And I didn’t even remember about that for a long time, not that it directly alters many other elements, but another misconception of context nonetheless.
But was Zadoc’s lie just a simple system error, or broadly speaking another interface distortion? If we take it at face value, it could mean that the Seekers, at that time, did not believe the Eins dragon was the same as Lagi…
Remember when Edge’s dragon first evolves after the Gigra fight, and Gash says “this must be the one” (another caveat to that, but not now). I believe we have a depiction of the Seekers themselves being very distrustful of the nature of just any old dragon. So I think they also might have some specific reasons in mind. But what’s most pertinent about that, is the suggestion that Lundi presumably couldn’t recall or articulate his own visions clearly enough that the Seekers had a clear match to that Tower Activation Incident. And presumably he wasn’t still with them when it happened. It’s inconceivable that they wouldn’t have had a lot of information on the event itself, by the time of PDS.
So keep this idea in mind: the Seekers know a lot more than they ever got to reveal to us directly, but they also have a lot of it wrong. Consider that in virtually the same breath Gash is telling us about how dragons terminated all the active ruins and Towers, he also tells us, with conviction, that Edge’s dragon is the Divine Visitor.
OK my third derailment, is the serious one! As I’ve already asserted in some ways, the return to the Underground Ruins of Uru, searching for Azel after she disappears, is one of the most crucial junctures of the whole plot. Azel is both the game’s title character and the story’s Macguffin. After recovering, perhaps miraculously, from the second great trauma in a few days, and discovering emotions she knows nothing about; Azel is compelled to look for answers in the only place she can imagine, the location where her existence began. Azel is searching for truth, and in following her we will find some as well.
I’ve given this a lot of thought, and I believe there is one ‘correct’ order to read the Uru Records in. The chronology clearly breaks down if you attempt any consistent left-right or right-left pattern anyway; but this way will actually follow a snaking, reverse S pattern:
We?ll soon have permission to implant that mechanism. With it, we should easily clear the targeted value. However, there is a serious defect.
Drone F07 - Thought Index 98 Failure. Drone F16 - Thought Index 94 Failure.
Our latest subject is doing fine. That problem has already been solved by manipulating its lifespan. We shall name this drone Azel.
A week has passed since the attack. The drone has not been found. She was probably stolen. She has not been completed yet. I only hope she does not become an instrument of destruction.
Report regarding the Light Wing. We have at last succeeded in developing the ultimate form of the dragon. But it is more than a dragon. It is a being far different? Something? perhaps even superior to ourselves? A messenger of the Gods.
The Institute, which considered the development of the Light Wing, a renegade project, has ordered us to delete all records regarding the Light Wing? But we have decided to record and seal all data regarding the Light Wing into one memory plate divided into 12 pieces called D Units, and scatter them throughout the continent? hoping one day a later generation would inherit our work?
Truth, such as it is, right from the ancient horses’ mouth. It doesn’t get any more consequential and focused than this. Because of the gravity these records have on the narrative, I felt each piece of information should be telling us something definite, and together they are telling us a central absolute. I’m more sure of that than ever, but I was caught by perhaps the one red herring in them, and followed the dead branch of evidence. Because there are two drones mentioned, I wanted to think the other one meant something as well, and the only other drone that could matter was the Sky Rider.
I mean it’s so simple right? After getting jerked around by fate and factions, two dragons with two drones finally reunite for the purpose only they together can fulfill - or sort of; with some substitute help along the way. I think every theory tends to look for unifying themes, and that seemed a clear one. Azel opens the gate, the Heresy dragon confronts Sestren, WE press the button. It’s a fairy tale ending, case closed!
Of course not, but I think half the theorizing I’ve ever done has been motivated by the search for a good replacement for that unifying theme ever since. So not to presume the motives of anyone else, but I’m presenting that both so that others may understand where this is coming from personally, yet also because I often see the same basic tendency in the form of material other theories present. So hopefully the motive itself will make sense.
That helps illustrate the very heart of the matter, because no, drawing such a distinction between the Light Wing and the Solo Wing is not actually arbitrary, not a bit! Yet perhaps we’ve all managed to miss why? 
And I even indicated the basis for that in the post you were replying to - the pride of place the D-Units and other material claim in the core narrative - so that may show just how elusive the understanding still wants to be. But I need to start over with some of that anyway:
First thing is, I had conflated my memory of the text on the D-Units - which don’t say too much - with the single paragraph in the manual about the D-Unit panel; and it’s “rumors of the fantastic powers generated when the units are fully assembled.” Which then brings up the fact of why it needs to be mentioned in the manual at all… because there’s a big chunk of real-estate on the menu screen dedicated to graphically tracking how many pieces of the Light Wing you’ve collected. That’s how central the Light Wing icon is on a system level, we’re actually viewing pieces of the true final form all along - and for that matter, the Dragon Phoenix, which is the all-round most devastating form of attack in the game, explicitly echoes the Light Wing form as well?
But once again, the IDEA of Light Wing itself occupies a central place in the very story. So in every possible sense, it is a core theme in Panzer Dragoon Saga, and it is entirely unique to that game. In those terms the Solo Wing could not really be more different, it is entirely represented by allusion and abstract mechanics. Hell the game even allows you to FUBAR getting it, if you sink Shelcoof for good before getting the dragon crest - leaving nothing to do there, ever again… that’s almost like some anti-symbolism there. Did they want you to be able to literally bury Lagi? And there’s nothing mysterious about the IDEA of referencing the forms of a few old friends there, only the mechanics employed are suggestive, but again all abstractly so.
Don’t get me wrong though, to be clear again I don’t even want to trivialize the symbolism of the Solo Wing at all. In fact I think it’s a lot more important, or certainly descriptive, than the Type_01 transformation in Zwei - which may be an outright incongruity. There’s a great deal of potential suggestion about the Solo Wing, which if anything also now seems more consistent than ever. But that’s another discussion.
To express it bluntly: Light Wing has DIRECT ties to the central themes of PDS’s story and mechanics; Solo Wing has virtually none at all. But also, and this is crucial, that very theme of the Light Wing is exclusive to that game. So hopefully that will finally close the circle…
Azel - the only being known that can force open a path to Sestren’s inner sanctum. When her origins are revealed we find out that she was ‘born’ in the same place and of the same expertise that also created;
Light Wing - an “ultimate” dragon form, that it’s own creators think is a “messenger of the gods”. Disobeying orders they bequeath that dragon form to a future generation: and in that generation the dragon that indeed inherits their work chooses as it’s rider a youth who’s life has been miraculously saved by a;
Divine Visitor - in fact the only force in this world that may resist the chains of fate that bind both Sestren and the world together in an eternity. And by the dragon’s own account, the very reason and purpose of it’s existence.
These three characters BELONG to Panzer Dragoon Saga, without any one of them, it’s story could / would not be told. There are other visitors to the story, but many have had their own stories as well. The most elusive unifying theme of all, is that there is no hidden unifying theme!
All three games are equally unique circumstances, the dragon is acting on completely different immediate crises every time. The Heresy dragon is a special agent of destiny, rather than a special forces commando. Lagi is a desperate gambit and Lundi is able to be it’s rider because of it’s unusual origins and their bond forged over time. Edge’s dragon “chooses” him because it exists to lead the Divine Visitor, which has now become a part of Edge. So what of the most mysterious dragon of all?
Activation of D Type 01? confirmed?
Lets just be pedantic for a moment and accept that is exactly what it should be. The D Type_01, by the only facts we know, must be the Armored Blue Dragon that appears in Panzer Dragoon. So why is it Sestren should be remarking on it like that? First the “impurity” is detected once more - and as it happens that is stated concurrent with an image of the Dark Dragon already flying through a tunnel - THEN an “activation” of the Type_01 is detected?
Now consider all the information pertaining first to drones, and then dragons as well, that we’ve been given. About half of all the material revolves around a conspicuous theme of control. Drones are special tools almost exclusively created for interfacing with more complex or difficult bio-engineered systems. Dragons - unlike all other known pure-type monsters, which just simply function - are “not easily handled by ordinary men”.
Atolm was “prepared” for Azel in the ancient age, and even early on she speaks to Edge about the powerful bond that must occur between a dragon and it’s rider. Azel herself is like a custom made key to the core protected functions of the Tower of Uru, the ancients aren’t big on allowing their most powerful weapons and installations to be fully autonomous.
So even as powerful and resourceful as the Heresy program is, it’s credible that it still may not be able to override such an intrinsic and crucial safeguard as a highest-of-high-tech dragon’s ‘protect key’ by will alone, and not with perhaps a very short window of opportunity. Perhaps it’s even a triviality for it to commandeer the dragon’s body, but it’d still be stuck in a lifeless vehicle without a key to the ignition. And from the only info we’ve been given, the usual key to a dragon, is a drone.
But the Heresy program IS very resourceful, unique even. We cannot know what the full nature of it’s relationship was to the Sky Rider, but what we do see before that rider expires, is a strong projection of images and will directly from it to Keil. Would a drone be able to imbue it’s own powers and protocols to a human? Probably not normally… but with an immortal sentient lifeforce that needs another rider to continue it’s immediate fight in the mix, that doesn’t seem too far fetched to me.
So consider how this situation would look if ALL of these entities are indeed distinct. The Heresy program is an indomitable force bent on an act of defiance, which it will carry forth by whatever means it can find. The Blue Dragon is a form and a function, but also perhaps a pattern of intelligence and intent of itself. Lagi is a rather special coolia, initially a physical being and host for the Heresy program but perhaps also incorporated into the collective of will, at the time when it’s corporeal being is sacrificed to the needs of the Heresy program’s objective. Edge’s dragon has gone through a deliberate transformation, in order to bond with the Light Wing, and become the liaison to the only force capable of ending Sestren’s dominion decisively.
By the time of Azel, ‘our dragon’ seemingly SHOULD have at least four distinct facets. Interesting that’s just what it reveals right before the end then, isn’t it? 
The Divine Visitor and the Light Wing are both peculiar to Azel, as is herself. It is their story, even as it is the conclusion of the Heresy dragon’s story. That Dragon indeed existed to lead the Divine Visitor, the truth was never hidden from us. That it’s peculiarities can seem so at odds with the actions and characteristics of the other manifestations of this collective force, is only to be expected, if they are not - nor were they ever - precisely the same.
So… that’s the foundation at least. Even with Panzer Dragoon we can’t expect everything to be perfect, but I honestly see this framework as seamless. I think it can withstand almost anything thrown at it, with hardly a dent to the chassis. I’ll even BEG anyone and everyone for criticism, anything at all. And this still isn’t even half the various secondary ramifications I’ve already considered, there’s still huge mysteries that remain as shrouded as ever, but most of the overt dissonances that used to bother me seem to fit together without much trouble now. Which then has a knock-on effect on virtually any other speculations.
