IoM vs New Republic

[DrStrangelove]

The NR should fall easily to the IoM. The NR response to the vong war was utterly incompetent . Not once did they use their superior industrial capacity to swarm the vong with numbers, or even concentrate their forces to repulse the initial invasion.Considering the GE built 25,000 ISDs in 20 years they should have easily wiped out the vong from that fact alone.

Tactically they refused to even bombard vong held planets until the war was almost over, much less BDZ one. And rarely if ever tried to at least concentrate their forces anywhere on any front to push back the vong.They placed entirely too much hope on the jedi who were unable to effect any sort of real military effect on the conflict until the end of the war with the help of deux ex planet.

Against a tactically competent foe of equal firepower and numbers such as the IoM the NR/GA is doomed to fall. this is echoed out in the EU when the GA falls to the Fel empire in the legacy era.

[Lord Relvenous]

Yeah, and battlefleet gothic (and a number of other sources: the space wolf novels, some of the Chapter Approved compilations, the Inquisition Sketchbook, BFG magazine, even as far back as the old Space Fleet stuff) also indicated millions of worlds.

I'd just point out that the same "million worlds only" argument can be applied to the Empire too, even though we have evidence for many more worlds (tens of millions, more likely billions.) so its a bit hypocritical to say "It works for SW but not for 40K"

I wasn't aware of the disagreement of sources for IoM's size, so i said nothing of the sort. I am willing to accept those resources, just as i am willing to accept the sources used to calculate the GE's size.

There are, however, more radical Magos who are curious enough to pull apart xeno technology to see how it works. After all, if there is knowledge to be gained, and it can be used for the betterment of Mankind's goals, why not?

The problem that i see here is that it wouldn't be a coordinated effort because of ideological differences, and that also many such projects are carried out in secret to prevent reprisals from the main body of the AdMec for heresy, and also for reasons of personal gain. A good example would be the instance in the Soul Drinkers series in which a lower level Magos gains possession of a vortex weapon and instead of presenting it to superiors with greater resources and training, instead assembles a team and attempts to crack it herself. I can't see such efforts gaining any sort of resutls in time to effect the outcome of the war due to an unrelated technological base.

[Junghalli]

Galaxy collisions should take many thousands of years. Long enough to fight for short-sighted reasons rather than worry about the larger problem.

Also galaxies are incredibly diffuse. Actual star collisions should be incredibly rare, although IIRC you may get bursts of star formation in colliding nebulae.

SOTE sourcebook page 74

The civilization of the Galactic Empire spans billions of stars, from Coruscant - the heart of the Empire - to remote Outer Rim worlds like Tattooine and Gall.

Star wars RPG 2nd edition revised, page 6

Before you can adventure in the galaxy, you better know something about it. First off, its Big - the Empire rules billions of worlds.

Hmm, one point I can see with that is they're vague enough that it might be possible that a lot of these are just empty barren systems with no habitable worlds or inhabitants that the Empire claims and rules on paper but doesn't actually do much with, sort of like the way nations on Earth claim pieces of Antarctica or the ocean floor. Especially if the Empire simply claims the entire galaxy (Palpatine would seem the type).

The first quote seems better in this regard, as it explicitly references inhabited worlds.

[white_rabbit]

A good example would be the instance in the Soul Drinkers series in which a lower level Magos gains possession of a vortex weapon and instead of presenting it to superiors with greater resources and training, instead assembles a team and attempts to crack it herself. I can't see such efforts gaining any sort of resutls in time to effect the outcome of the war due to an unrelated technological base.

Um, I'm typing this from Vague memory here, but as I recall, she was GIVEN the Soul Spear by a higher level magos and told to figure the damn thing out.

Its called delegation.

It was just unfortunate that she turned out to be a Tzeentchian stooge.

JUST AS PLANNED!

[Teleros]

Why, exactly, would 1/3 of the population suddenly be attacked by daemons? what makes SW sapient beings any more susceptible to PotW than the countless trillions upon trillions of humans and other aliens in 40k that don't have daemons popping out of their heads daily?

If the galaxies are overlapping a large chunk of the Star Wars galaxy is going to be in the Eye of Terror. A bit more here and there in the few other free standing warp storms (Largest two being the Storm of the Emperor's Wrath and the Maelstrom). Maybe less than a third, but still a decent chunk are going to be in places where the laws of physics are laughed out of town.

I agree with HSRTG that having NR worlds stuck in the Eye of Terror etc is going to be... interesting, but I'm not sure about the daemons, given the whole "no other enemies" etc in the OP.

[Aaron]

I agree with HSRTG that having NR worlds stuck in the Eye of Terror etc is going to be... interesting, but I'm not sure about the daemons, given the whole "no other enemies" etc in the OP.

Well the world in Dead Sky, Black Sun was throwing off Ventris and his buddy (two experianced Ultramarines) and killing the two Guardsman the renegades had liberated. I imagine that the NR worlds that are thrown into the Eye are eventually going to be filled with people gone insane, daemons or no daemons.

[Darth Hoth]

Against a tactically competent foe of equal firepower and numbers such as the IoM the NR/GA is doomed to fall. this is echoed out in the EU when the GA falls to the Fel empire in the legacy era.

I thought it was pretty much established that 40k weaponry was inferior to SW such by an order of magnitude. Not that it matters all that much here, as the NR would be utterly swamped by sheer numbers, but that is hardly "equal firepower".

[Fingolfin_Noldor]

Against a tactically competent foe of equal firepower and numbers such as the IoM the NR/GA is doomed to fall. this is echoed out in the EU when the GA falls to the Fel empire in the legacy era.

I thought it was pretty much established that 40k weaponry was inferior to SW such by an order of magnitude. Not that it matters all that much here, as the NR would be utterly swamped by sheer numbers, but that is hardly "equal firepower".

If I recall Connor's analysis threads, their weaponry can be close to NR weaponry, except that their range isn't as good by several times.

On the ground, the Stormtroopers get stomped big time.

[DrStrangelove]

Sorry i'm used to being able to edit. Its supposed to say roughly equal firepower.

[Lord Relvenous]

A good example would be the instance in the Soul Drinkers series in which a lower level Magos gains possession of a vortex weapon and instead of presenting it to superiors with greater resources and training, instead assembles a team and attempts to crack it herself. I can't see such efforts gaining any sort of resutls in time to effect the outcome of the war due to an unrelated technological base.

Um, I'm typing this from Vague memory here, but as I recall, she was GIVEN the Soul Spear by a higher level magos and told to figure the damn thing out.

Its called delegation.

It was just unfortunate that she turned out to be a Tzeentchian stooge.

JUST AS PLANNED!

The project was undertaken in secrecy. Whether that was decided by the working Magos, or her immediate superior, as you said (and i think you're right, i don't have the book to check) the fact remains that the possession of the spear was kept in secret so that the discoverer could reap political and beaucratic benefits from the unraveling its technologies. It was one of the biggest finds in recent history, and yet it was a given that it should remain secret until the project was completed, which seems to indicate a individualistic trend in Magi, Magi being plural of Magos.

[white_rabbit]

The project was undertaken in secrecy.

Does one part of a military industrial complex immediately inform all others when they discover the equivalent of an alien artifact ?

I don't on the face of it, disagree with you, the Ad-mech are obsessively secretive and possive of shiny things, and individual, high ranking types like Khobotov have a large degree of autonomy and personal resources with which to prosecute their own agenda with.

But in the face of readily available samples of something as fantastically useful as certain aspects of SW tech, I don't think you can expect a similar degree of insular stupidity, even Tech-priests have to do what they are told, and its going to be difficult to keep such a "discovery" secret, unless its a similar situation to the Soulspear.

I.e. an arsehole like Khobotov nips out and procures "it", then legs it back to his Forgeworld to play with it.

[Lord Relvenous]

Yes, that's true. The example given was to illustrate the fact that the members of the AdMech do not cooperate readily with each other, nor work as one cohesive body. So people saying "the AdMech would begin to recreate the technology" seems silly to me because there really isn't any unified efforts directed by the AdMech other than the search for STC artifacts, and even that can be fractured. Maybe the abundance and obvious benefits of SW tech would change that though.

Also, even if the AdMech were to unravel some of the secrets of Star Wars, how long do you think it would take them to build of the infrastructure necessary to produce the new technology in any meaningful numbers?

[Connor MacLeod]

Not as much time as we may think, though. Sienar, SoroSuub and KDY are publicly traded companies. They want to be found. The Rogue Trader is the ideal agent for these contacts; with nigh inviolable rights to large amounts of valuable commodities available on his personal approval alone. They can play Good Cop/Bad Cop with the Inquisition, to peal SWverse polities away from the NR. The Inquisition's experience in dealing with "bussinesses" and "governments" in every possible meaning of those words is only a plus.

Actually I suspect that the Rogue Traders would be kept far away from the New REpublic. Given the sample of most Rogue Traders we've seen, even the best of them can be fairly greedy and self serving (not that they're the only ones.) Access to all the technology(freely avaiable) in the New REpublic is going to be a massive temptation (FTL travel that allows you to cross the galaxy in days and doesnt require access to the warp? Non astropathic communication that can cover tens or hundreds of light years at a pop, nevermidn hyperwave/Holonet? FTL sensors?) RT' are known to dabble in or employ xenos tech, so they won't hesitate to emplyo this.

More to the point, even if the RT is somehow completely loyal, ,there are other factions that would conspire against them: The Navigators won't like hyperdrive (The Imperium wouldn't need the three eyed mutants anymore), the AdMech won't tolerate anyone having access to Free Tech (unless its through them), etc.

If anyone is goign to be making contact, its likely the Inquisition, given they're the best connected (And most experienced) at doing what we might term "covert ops",) and enough of them are fanatical enough not to be turned by the temptations of technology.

And even then, there's still goign to be problems. For the most basic part, they need to LEARN about that galaxy, and you know how the Imperium feels about "learning about heresy" - someone will do it no doubt, but you can also be sure someone in the Inquisition is going to be suspcision of it (and simply be in favor of the "Purge the unclean" approach.) Hell, do you even know if Basic and Imperial Gothic are even remotely similar? the Language barrier alone is going to be time consuming. Then there's getting maps and finding out important information. AGain, that won't be as difficult as it would be against the Empire, no, but its still time consuming (And as below, there will be a number of complications on the Imperial side.)

That time may well be available. Though the universes are overlapping "ven diagram" style, which portions are overlapping aren't specified. Distance from major fleet bases and the well-traveled warp roots to them will slow mobilization, which is going to be massive in the case of a galaxy threatening Crusade. Its highly likely that the first institutions to react will be the Navy, the Inquisition, and Rogue Traders

But as I alluded to above, Imperial Politics are going to be a problem. The Navigators will have reason to restrict access to the SW galaxy (or to see it purged completely outright.) The Ecclesiarc hy will want conversion of or purging the "foul xenos-loving and tech using aliens." The AdMech will want to be the AdMech (be the only ones to get their hands on and thereby control SW Technology, all the while keeping everyone else from doing it.) - nevermind the various other groups (the Guard, the Navy, etc.)

Fear of "discovery" of the NR and what it has/can do is probably goign to limit the extent or capabilities of any "stealthy" or subversive efforts. A simple, massive crusade is (from the Imperial standpoint) much simpler. Its not as if they won't hesitate to kill their own people if there's threat of taint or heresy.

Of course, I have no doubt that if/when they get information, they can do some real damage being sneaky (though I was thinking more in lines of the Sabotage and ASsasins. Having a Vindicare or Callidus assassin kill Fey'Lya will have all sorts of repercussions.)

I understand the second sentence clearly enough, but I'm not quite sure on your meaning in the first. Could you clarify? This may be a "duh" thing, but I'm in the process of packing for a move and it's midnight where I live.

The Vong infiltrated the SW galaxy well before TPM, and were gathering information/slaves and probably fucking around with things in the SW galaxy long before they made their move in the NJO. For example, Nom Anor was fuckinga round with the post-Palpatine Empire (ref: Crimson Empire 2) and we know he was instrumental in causing numerous revolte and uprisings that forced the New REpublic to play the "peacekeeper" role (the beginning of Vector PRime.)

The Imperium, in this case, will NOT be having all that "prep time" to fuck around with the SW galaxy, to infiltrate the government, to find and exploit traitors in the Government, ,etc. It will still be the same semi-corrupt and semi-inept New Republic, but without the Vong fucking around with things, I doubt the NR will be paralyzed for nearly as long as they were in the NJO without it.

Surely, but where will it be launched from? How long will it take to mobilize? It all depends on the point of contact between the 'verses, which isn't specified. You've brought this up already and the thread author hasn't modified the conditions.

Were I the Imperium? I'd throw the Astartes and Inquisitional assets into the galaxy first, with the primary purpose of sowing chaos and destruction especially at the infrastructure. Imagine what a thousand or more Space Marine Chapters and the full might of the Inquisition (and its forces) to further sow chaos.

Of course, they won't be able to leave the AdMech out of it either, because the AdMech will want tech, so they'll probably be attackign too.

In the meantime you can expect some Warmaster to be appointed and a Crusade to be announced or mustered, ,before being unleashed on the galaxy. That would take longer, but probably not nearly as long as you'd think. Even a Segmentum's worth of assets could do much to distract/delay the New REpublic, esp with the AStartes and Inquisition (and AdMech) already in there. As time goes on the Imperium can bring more and more forcecs to bear into the galaxy. The key will be keeping up the momentum, keeping the NR on the defensive, not giving them breathing space (even a year or two) with which to build up naval assets.

Agents like Inquisitors and Rogue traders operating with their institutional experience and knowledge of local resources are going to chase the Navy as fastest responders. At least until we know a distance between the area of operations and a major logistical hub (like, Hydraphur/Cadia sized at least for what we're talking about). The battlespace will be confused as all hell to say the least, and planning anything other than a general advance into it is going to take a while.

I actually kind afigure it woudl happen something along the lines of like what happened in the novel Eye of Terror or the Sabbat Worlds crusade, on a larger scale. You'll have a single person (or a handful of people) masterminding the invasion and leading it. Indeed, that's the whole point of a warmaster, isnt it?

Like I said before, ,what is going to be confusing is attempting to control who/what gains access to the Imperium. The greatest danger here to the Imperium is what happens when some groups in the Imperium start getting hold of SW tech. (I should note this has even more frightning implications if the other factions in 40K were involved - esp Chaos and the Orks. Can you say "Looted Star Destroyer/Executor?")

[Connor MacLeod]

Why, exactly, would 1/3 of the population suddenly be attacked by daemons? what makes SW sapient beings any more susceptible to PotW than the countless trillions upon trillions of humans and other aliens in 40k that don't have daemons popping out of their heads daily?

If the galaxies are overlapping a large chunk of the Star Wars galaxy is going to be in the Eye of Terror. A bit more here and there in the few other free standing warp storms (Largest two being the Storm of the Emperor's Wrath and the Maelstrom). Maybe less than a third, but still a decent chunk are going to be in places where the laws of physics are laughed out of town.

a.) The OP specified "all other opponents are removed" This presumably includes the threat from the Eye (We must assume the Imperium pacified it somehow)

b.) So what? Overlapping doesn't tell us how they'd do it. Depending on how it goes, they may get little or no contact with the Eye. Yes, there are other places like tha Maelstrom, but they aren't nearly as large. If you go by how NL describes it (which would actually make the most sense and give the Imperium the best oppotunity TO strike at the SW galaxy if for some reason they needed the AStronomican in SW to do it.) there prboably wouldn't be much if any such overlap.

Further, the situations would have changed for the stipulations in the OP to be true, and the SW galaxy isn't like 40K which is ALSO (as I've already explained many times) going to affect the Chaos/Warp factor.

The real threat is if cultists or some such got ahold of hyperdrive equipped ships. Even personal ones or freighters. If that happens, all bets are off for both sides.

[Connor MacLeod]

Against a tactically competent foe of equal firepower and numbers such as the IoM the NR/GA is doomed to fall. this is echoed out in the EU when the GA falls to the Fel empire in the legacy era.

I thought it was pretty much established that 40k weaponry was inferior to SW such by an order of magnitude. Not that it matters all that much here, as the NR would be utterly swamped by sheer numbers, but that is hardly "equal firepower".

If I recall Connor's analysis threads, their weaponry can be close to NR weaponry, except that their range isn't as good by several times.

Depends entirely on which calcs you go by. The more conservative could put the Imperium's firepower an order of magnitude or two below SW, while the higher end ones could put it well above SW's (oom easily) I tend to believe its within an OoM or so of SW firepower, ,bu tthat's just me (and it can depend on the warship and the weapons its got.)

Note that even if they have less firepower, the Imperium has certain mitigating factors:

- There is a massive defensive/toughness disparity in their favor. Imperial ships can take hours of punishment from weapons of roughly their own firepower. SW ships can do minutes (or seconds) at best, and tend to explode more spectacularly when destroyed (IE ISD blasted by Mon Cal Cruiser in ROTJ.) The disparity is more than enough to offset lower firepower (They can't hit as hard, but they can take alot more abuse, long enough to possibly allow them to take out the enemy.)

- They have alot more ships, at least initially. Assuming they're able to concentrate in a reasonable timeframe, they can probably achieve numerical superiority against NR vessels (This is a short term advantage and will depend entirely on how quickly, if at all, the NR can get its industry in gear after they get attacked.)

On the ground, the Stormtroopers get stomped big time.

That'll depend entirely on who the Guard deploys to fight (as in, which Regiment, since they're not all created or equipped equally) as well as the NR (troop quality iwll vary there as well.) Cadians or Vostroyans or Tallarn might be one thing, but if they deploy a regiment with more Napoleonic or Feral/feudal traditions towards warfare I doubt the NR would have nearly as much difficulty unless their troops are similairily low end.

I should also note that deploying battle droids is still done, even if not (quite) on the scale of the Separatist sin the Clone Wars. I'd imagine facing a group of droids like a YVH model would not be pleasant, possibly even for the Astartes.

[Connor MacLeod]

The NR should fall easily to the IoM. The NR response to the vong war was utterly incompetent . Not once did they use their superior industrial capacity to swarm the vong with numbers, or even concentrate their forces to repulse the initial invasion.Considering the GE built 25,000 ISDs in 20 years they should have easily wiped out the vong from that fact alone.

The Vong also, through a myriad of reasons, not the least being the already-mentioned fact the Vong had infiltrated and were well entrenched in this galaxy and messing around with things, were given enough time to establish and buidl up their forces before the NR got its ass in gear and mobilized back. On what basis do you assume precisely similar conditions will exist for the Imperium, pray tell? Did the OP say that the Imperium got decades to screw around with the SW galaxy behind teh scenes too, or did I miss that?

Tactically they refused to even bombard vong held planets until the war was almost over, much less BDZ one.

I've already mentioned this. Their lack of military initiative is the big disadvantage, but its hardly an insurmountable one for them.

Mind you, that wasn't uniform. as I recall there were segments of the NR prepared to commit genocide against the vong using BiowarfarE (at least until they were stopped by the "Good guys") and I'm pretty sure they had Chiss help in that. Especially after the Vong starrted doing it. This is why I tend to labe the weakness as "lack of military intiative" in fact - some people in the NR probably could do it (I'm looking at you Garm Bel Iblis) but they wouldn't do it at the get go (at most, it would probably be retaliatory, just as invading the 40K galaxy would be, if they actually contemplated that.)

And rarely if ever tried to at least concentrate their forces anywhere on any front to push back the vong.

Actually, they did it quite a few times. It happened alot in Star by Star, Destiny's Way, the Agents of Chaos duology, the Allston Duology, etc. Part of the problem is is that they didn't do it early enough when it woudl do some good. (There was also the fact that the NR government was, IIRC, infiltrated. We know of at least one person funnelling them information - ie Viqi Shesh - and probably there were others.)

They placed entirely too much hope on the jedi who were unable to effect any sort of real military effect on the conflict until the end of the war with the help of deux ex planet.

They did? As I recall they didn't really pay much attention to the Jedi during the crisis until midway throug the NJO. In fact, for a good deal of the early bits had people hunting them down. The Earliest I can recall the Jedi having a "real military effect" is Star By Star, and you didnt really start seeing Jedi/NR cooperation until later on then.

Against a tactically competent foe of equal firepower and numbers such as the IoM the NR/GA is doomed to fall.

"tactically competent?" That'll depend entirely on whose in charge and what forces that you have in the invasion. Yes, they have some competent forces, ,but they also have regiments that would probably due the "stand and deliver volleys from fifty paces and charge with bayonet" style tactics as well.

And I wouldn't call someone like, say, Hector Dravere "competent." He went to the Zapp Branigan School of Militery Theory, for crying out loud. (most memorable for saying "I could choke the Eye of Terror if you give me enough men.", or something to that effect.)

this is echoed out in the EU when the GA falls to the Fel empire in the legacy era.

Bad analogy. The Fel Empire has alot more in terms of parity with the GA than just firepower duraility (industrial potential, FTL capability, FTL sensor and communications, etc.) And from what I remember of the GA in the Legacy era, they were even weaker and more inept than they were at the starrt of the NJO era (or in the LOTF era, for that matter.)

[Darth Hoth]

Depends entirely on which calcs you go by. The more conservative could put the Imperium's firepower an order of magnitude or two below SW, while the higher end ones could put it well above SW's (oom easily) I tend to believe its within an OoM or so of SW firepower, ,bu tthat's just me (and it can depend on the warship and the weapons its got.)

Fair enough, then. Has this been discussed around here? I searched the old SW vs 40k threads and did not find anything at first glance, beyond the 610 gigaton torpedoes.

[Connor MacLeod]

There's a sticky thread at the top of the forum, with the relevant topics. It includes the various calcs and analysis relevant to a debate.

[Setzer]

Okay, making another clarifying statement:

The IoM does not have infiltrators beforehand. They can develop infiltrators before launching their primary assault, but they do not immediately have them in place at the scenario's beginning.

[Falkenhayn]

Roll out in a 2km long ship plated in gold, and I gurantee that someone in SW'verse will sit you down with a protocol droid long enough to figure out your language. DW didn't seem to think it was a big deal in his fanfic, though that may have been to keep things moving, and it's not like Feddy computers have anything on a Cogitator Bank.

And even then, there's still goign to be problems. For the most basic part, they need to LEARN about that galaxy, and you know how the Imperium feels about "learning about heresy" - someone will do it no doubt, but you can also be sure someone in the Inquisition is going to be suspcision of it (and simply be in favor of the "Purge the unclean" approach.) Hell, do you even know if Basic and Imperial Gothic are even remotely similar? the Language barrier alone is going to be time consuming. Then there's getting maps and finding out important information. AGain, that won't be as difficult as it would be against the Empire, no, but its still time consuming (And as below, there will be a number of complications on the Imperial side.)

Indeed there will be. Like figuring out what the fuck is going on. The first people to do that will be the ones most adept at autonomous operation.

Fear of "discovery" of the NR and what it has/can do is probably goign to limit the extent or capabilities of any "stealthy" or subversive efforts. A simple, massive crusade is (from the Imperial standpoint) much simpler. Its not as if they won't hesitate to kill their own people if there's threat of taint or heresy.

Yes its simpler. But you're over-applying Occam's Razor. The simplest concept is not the simplest operation to execute. What you are proposing is a military/logistical undertaking that makes the Sabbat worlds look like a cat-fight. It takes time for word to travel, time to assemble materiel and fighting men. That time is much, much less if their is a suitable hub nearby, with well-established warp routes to and from. Depending on where the galaxies overlap, and given amounts of empty space, it may well take months or years for the polities to define each other's territory. Otherwise, the only certain information about the battle space is each side's knowledge of its own possessions.

Of course, I have no doubt that if/when they get information, they can do some real damage being sneaky (though I was thinking more in lines of the Sabotage and ASsasins. Having a Vindicare or Callidus assassin kill Fey'Lya will have all sorts of repercussions.)

That's the point. You don't send a military force capable of threatening the security of a galaxy off half cocked.

As you know, the Imperium works on bureaucratic inertia. No doubt you are right in saying that numerous portions of the IoM will go on the offensive on their own, once they've got some idea of what's going on. But that's the problem. It takes time for information to work its way through the Inquisition, through the Navy, through Rogue Traders. Information that the IoM requires to even contemplate planning the maneuver you're suggesting.

The whole planning phase of this operation is swept under the rug in favor of what we have information on; industrial potential, firepower, type of government, institutional experience, etc. It may well be that the GE can make eleventybillion SD's every two weeks; what's the biggest number they've ever commanded (successfully) at once? What's the largest distance they've had to coordinate forces over, and how big were they? The same applies to the IoM.

The Imperium, in this case, will NOT be having all that "prep time" to fuck around with the SW galaxy, to infiltrate the government, to find and exploit traitors in the Government, ,etc. It will still be the same semi-corrupt and semi-inept New Republic, but without the Vong fucking around with things, I doubt the NR will be paralyzed for nearly as long as they were in the NJO without it.

How do you know?

The standard response to any threat in the IoM is system of threat levels. Each level roughly corresponds to a level of administration, from planetary to segmentum. The fact that the two sides are being dropped on top of each other with little if any knowledge of their opponent's geography is supremely important. Fighting, at least initially, ought to be localized and diffuse, meaning their are large spaces free of violence between points of conflict.

This will confuse the shit out of both sides. The Imperium is better off at this, as their experience is fighting dozens of brush wars at the same time. They are very, very good at it. So why should they change? The Administratum will respond in the familiar way to lower level calls for reinforcement by channeling forces to each fight individually, prioritized by the threatened area's value to the IoM.

Winning lots of local conflicts is a great way to use SW's coms for your own purposes. More information is always a good thing, even if extracted from a peace served up on a bayonet. Neighboring states may well become more accomodating to the IoM. Whether the reverse is true is another thing, but "submit or die" worked well enough for Ghengis Khan. Especially if you have a track record of skull pyramids.

Were I the Imperium? I'd throw the Astartes and Inquisitional assets into the galaxy first, with the primary purpose of sowing chaos and destruction especially at the infrastructure. Imagine what a thousand or more Space Marine Chapters and the full might of the Inquisition (and its forces) to further sow chaos.

Of course, they won't be able to leave the AdMech out of it either, because the AdMech will want tech, so they'll probably be attackign too.

I don't know how all of the objections you've raised to my points so far don't apply to this. How do your inqusitors and Space Marines know where to go? To the extent that anybody in the Imperium can tell an SM chapter anything other than where the warzone is. What they do there and how they do it is entirely up to them, though they are adept at improvising a command structure around the most senior chapter master and liasing with other Imperium forces.

In the meantime you can expect some Warmaster to be appointed and a Crusade to be announced or mustered, ,before being unleashed on the galaxy. That would take longer, but probably not nearly as long as you'd think. Even a Segmentum's worth of assets could do much to distract/delay the New REpublic, esp with the AStartes and Inquisition (and AdMech) already in there. As time goes on the Imperium can bring more and more forcecs to bear into the galaxy. The key will be keeping up the momentum, keeping the NR on the defensive, not giving them breathing space (even a year or two) with which to build up naval assets.

How long does it take to mobilize a segmentum?

I actually kind afigure it woudl happen something along the lines of like what happened in the novel Eye of Terror or the Sabbat Worlds crusade, on a larger scale. You'll have a single person (or a handful of people) masterminding the invasion and leading it. Indeed, that's the whole point of a warmaster, isnt it?

Well, yeah. We've just never had any Warmaster besides a certain one command more than 20 Chapters of SM and single digit billions of Guardsmen. You'd require dozens of Slaydo/Macharius/Macaroth level officers. Do such numbers exist?

Like I said before, ,what is going to be confusing is attempting to control who/what gains access to the Imperium. The greatest danger here to the Imperium is what happens when some groups in the Imperium start getting hold of SW tech.

Don't the Chiss control a pretty broad swath around the perimeter of SW galaxy? Sending a crusade blundering into somebody who actually had their shit together is bad news.