The argument so far....

Windlily:
       In Super Nova when Stan's staggering around in the memory archive place on Brunnis, the first disk he touches is of someone receiving an ultimate honor award for a victory in one of the battles against the Insect race. The next one is someone writing about the sun beginning to fail, then he bangs into the one with the Time Prophet. And that one was from 5,000 years ago. It seems to me that the archive runs from the least recent entries toward the door Stan entered through, to the most recent toward the back (the eyes of the head building of the Memory Catacombs...right?)

Flare [frowning]:
       I'm not so sure about that. If that's the way the Memory Catacombs are arranged, then Kai's should be the very last one, right under the 'eyes', surely? And it isn't. There are 'slices of life' both before and after it.

Windlily:
       Hmm.... Well, for the current query that doesn't really matter: I still have this problem with a Brunnen-G warrior getting an award for fighting with the Bugs before the Brunnen-G left for the Light Universe. You see my dilemma?
       Now, are we ever told where the Insect Wars occurred? (as in Light or Dark Universe...)? Or just that the Brunnen-G lead humanity to victory in them? Bear with me here...have the fen just assumed that the War occured in the Light Universe? A thought here to back that up...Stan and Zev keep saying that there are no humans in the Dark Zone. Well, there are, right? We've run into the Klaagyans...and they had at least three other planets full of humans before they blew themselves into smithereens. Also, the Brunnen-G CAME from the Dark Zone, so there were humans there (perhaps a lot of them) a long time ago. Maybe after the Insect Wars there was a mass exodus by various planets to the Light Universe and the Brunnen-G decided to hang out in the Dark Zone for a bit longer?
       Huum...okay, continuing on with that train of thought...humanity has defeated the Bugs and for some reason a bunch of them decide to go to the Light Universe. Off they go, with the essence of HDS hanging out inside one of them, thinking that he'd be away and free of the Brunnen-G and run amok. Which he does for a thousand years or so, then Brunnis Prime starts running out of gas and the Brunnen-G finally make the crossing. In that thousand years the Brunnen-G have assimilated the Insect technology and bring it with them. Wouldn't that explain DP-14's surprise at finding Insect tech among the Brunnen-G when he kills Kai?

Flare:
       I think you could be right about the Insect Civilisation originating in the DZ: the clincher is Krato's "slice of life": unless he went back to Brunnis to die, which seems unlikely.
       So, as you say:-

       How did His Shadow get into the Light Universe? Did he just follow the Brunnen-G through the fractal core, or did he tag along in some Brunnen-G's mind? If so, that means that the first Divine Predecessor was a Brunnen-G? What an icky thought. Is it reasonable, though?

       Sure is! In which case, having a Brunnen-G destroy the Divine Order in the LU is a neat balance. But the Divine Order was actually developed by survivor(s) of the Insect Civilisation - so did an egg (like the GigaShadow eggs) come through the fractal core in one of the Brunnen-G ships, rather than in one of their minds? Or was the IC already present in both Universes? Actually, I'd say not: surely the Brunnen-G would have battled the IC immediately, if they found it in the LU? Here's a slight variant on your idea - see if this scenario makes sense.....
       The Brunnen-G defeat the IC in the DZ, and all goes quiet. Some time later, Brunnis breaks down and they leave for the LU - carrying IC survivors with them. In the process, their ships lose some of their recorded data (it happened to the Lexx, and the ships all use the same - Insect - technology: you're right, the Brunnen-G did take it over after the IC was defeated). The Brunnen-G colonise New Brunnis; everything trundles along peacefully; they resume their roles as poets, romantics and scholars, and lose most of their acquired arts of war - so when the IC (in the shape of the Divine Order) resurfaces, they no longer have the weapons to fight it. The Divine Order grows more powerful, and destroys New Brunnis - and redevelops insect technology using pieces of Kai's ship.......and 2000 years later it has practically taken over the universe. (Well, OK - galaxy, at any rate!)

Windlily:
       Hmmm...... OK, I agree with most of this, but there's one big problem: Kai (and, we'll therefore assume, the Brunnen-G as a whole) didn't know that the GigaShadow or HDS were survivors of the Insect Civilisation until they confirmed it at the very end of GS, right?
       Now, step even further back with me into the cycles of time....[evil, insane laugh.....]
       OK - I've been thinking: how did humans get to the Dark Zone in the first place? We'll assume that sometime in the future-past that humanity left it's homeworld in the Light Universe to scatter amid the stars. One group of colonists (with the Brunnen-G ancestors amongst them) through accident and happen-chance (if we stay true to the basic 'dumb-luck' logic of the series) 'fell' through the fractal core and found themselves stuck.....

[Flare nods - which is quite possible: we already know that it's not so easy to travel through the core: it seems to disrupt information systems.... I don't see why humans couldn't have evolved in the Dark Zone, though......]

       ..... So, being human, they did what humans do best - scattered to colonise what available worlds they could find, and survive! And, of course, in doing so, they run afoul of the dominant sentient species in this part of creation - the Insect Civilisation.
       So the rumbles of war begin.....

Flare:
       Ye gods! This is getting deeper and deeper!!....

[Windlily laughs as she hands Flare a shovel....]

       I'll have to print out everything we've considered so far and watch the films again with the printouts and diagrams and a big red pen!! [Flare gazes stoically into the distance - "I'm going next door, now. I might be some time......"]

Windlily [laughing]:
       I can imagine!
[Flare reappears, having spent the last three cycles of time (relativistically-speaking) chasing rings around the universe]
       Have a good visit?

Flare:
       Well, it was interesting!

Windlily:
       OK - here's another thought:-
       Brunnis breaks down and they leave for the LU - carrying IC survivors with them.
       I don't think they'd have tolerated survivors, neh? But then, in some humans the lust for power and control burns like a sun...... perhaps HDS promised a Brunnen-G supreme power and control if he would take HDS' 'essence' with them? (And of course an egg or two.....)
       Though that still begs the question, why didn't HDS have the Bug technology when he swooped down on New Brunnis? I think it's perhaps more likely that the HDS essence got into a host and fled through the Fractal Core at the end of the war to get away from the Brunnen-G; or in desperation (or better yet, dumb luck!) got shoved into the Fractal Core and ended up in the Light Universe. Hmmm.... Now that works!
       OK....... So we have a wounded and damaged HDS essence/Bug loose in the Light Universe. All he has to work with is what he came through with..... no access to his own tech.... He manages to find a good planetoid to crawl into, and manages to 'possess' a human, and the first His Divine Shadow is created. He is busy working on his takeover of the Light Universe when the Brunnen-G show up...... You nailed the rest.
       Sound feasible?

Flare:
       Overall, this sounds good! Of course, the shadow essence might have come across in a different host than a Brunnen-G: I've always assumed that there was some sort of possibility of travel between the two universes (defending the Light Universe from the evil of the Dark Zone is, after all and purportedly, HDS' raison d'etre - OK, I know creating a 'bogeyman' is a good way to keep the masses in line, but everyone seems to know about the Dark Zone, even Zev, who's spent most of her life in a box. (Or have I misunderstood the script?) Hmmm........ that opens up a whole new area for discussion. Care to comment?).
       So the shadow essence enters the LU in a human host, leaves the host as soon as it finds an appropriate 'home' (how does the GigaShadow egg get there?), finds another appropriate host and starts taking over the LU. I have a different scenario - see how this sounds.....
       Perhaps it was the GigaShadow itself that fled the DZ/fell into the LU after the IC's defeat at the hands of the Brunnen-G. After all, Kai says it has been dormant for millennia. And while it's too big to pass through the Fractal Core now, it was probably smaller in the past, and would have been able to survive the transition. So it curls up in the Cluster (it might even have accreted the physical matter of the Cluster around its body throughout the millennia: I think that might be pushing the idea too far, but I thought I'd throw it in anyway!!), grows bigger, and broods on its revenge, while the more mobile part of its being - the shadow essence - is set free to take over the first human it encounters (it wouldn't matter who, though the weaker the individual the better...). This of course raises further questions on the relationships between the Shadow essence/protoblood/the GigaShadow/that double-damned cloak [Flare spits plasma and glares furiously at it. Why can't we get this resolved!? Is it something so obvious we're just missing the point?] - your comments would be most welcome!
       Before I close this section, here's the result of my ponder on timescales. Assuming your theory about the 'slice of life' storage is correct (I'm not entirely convinced - Kai's being out of sequence bothers me - but the basic theory is logical, and accords well with what we already know) then the Insect Wars must have been more than 5,000 years ago. Krato's 'slice of life' comes before the question about the mineral deposits on Irillium (and somehow, I can't imagine anyone asking such a trite question if the Brunnen-G were at war at the time!!), and we know from the Time Prophet's words that that was 5,000 years ago. So the Brunnen-G arrived in the LU somewhere between 2,000 and 5,000 years ago. (I still think that's a hell of a long time to keep a hairstyle going....). And it looks as though my thoughts on the Time Prophet may be right. She can be questioned by people from both Universes, and throughout time: I'm sure she exists in a separate continuum and is probably near-immortal.....

       One last question. If, as seems most likely, the Insect Wars took place in the Dark Zone, how did the Brunnen-G become famous in the Light Universe? Other humans came from the DZ and spread the word? Or did the Brunnen-G just have excellent PR staff.....?