How much of Star Wars galaxy could Guilliman conquer with his Legion?

[Emperor Tippy]

On screen troop counts do not back up that fact, and with the Disney acquisition most of the high end calcs for SW go out the window IMO, but we still have WH40K ships having ton for ton superiority.

Disney canon is a joke written by individuals with raging hateboners for Star Wars.

Even ignoring that, you still have tiny little things like ten thousand Star Destroyers, populations that dwarf Warhammer, and multiple Death Stars.

The DS 2 alone is more military tonnage than every single human flagged vessel sourced in all of Warhammer lore. By at least an order of magnitude. And it was built in a handful of years.

Just compare the effects of the Mandator IV-class Siege Dreadnought with what your average Exterminatus fleet can do.
And 40k is at an actual disadvantage compared to 30k because of the Horus Heresy, the Scouring, and all of the other nasty crap that happened to the Imperium.

And if you ignore the truly idiotic SW canon, every SW capital ship is qualified to carry out a Base Delta Zero in a period of hours.

As to A.I. and droids, well, IMHO what the Mechanicus termed Abominable Intelligence was orders of magnitude more capable than any droid.

Perhaps, but utterly irrelevant. Droids flatly violate every single precept around AI. It doesn't matter how capable they are, this is the single strongest prohibition in all of 30K/40K. AI is to be destroyed immediately upon contact with no qualification, hesitation, mercy, or concern over cost or collateral damage. The ONLY entity in all of the IoM who is allowed to sanction any kind of AI is the Emperor in his own person.

So yes, droid alone either mean that Rowboat goes full total war against the whole of the SW galaxy or faces near universal rebellion as his forces turn on him. The Ultramarines themselves are the ONLY faction in his forces that might remain loyal if he tries to play nice with the AI users.

In fact I doubt that the average droids are much more capable than your average servo skull or other bits of tech the Machanicum used prior to the HH.

In fact half the Machanicum joining in on Horus's side is IMHO indicative of the fact that they were very unhappy with the dictates of Mars and the limitations put on them where various forms of research were concerned, and even among the Loyalists there were a fair few that wanted to dabble into forbidden knowledge, like Belisarius Cawl.

I mean, have you ever read any 40k material where at least one higher-up cogboy didn't want to say screw it and play around with A.I. or Necron tech?

IoM computer technology and automation technology is lightyears behind SW computer and automation technology. And yes, the average droid would blow basically anything short of the "true" Abominable Intelligence out of the water when compared to IoM automated systems. Or even servitors.

 

[Agent23]

You are picking and choosing which canon to follow.

As to exterminatus, well:


One hit, one ship, Base Delta Zero Equivalent.

Sorry, but ton for ton Warhammer warships are orders of magnitude superior.

As to the Jedi, well they are way too few to effect any meaningful impact, and 40k psykers will only benefit from the extremely calm warp.

The Coruscant's various political systems have proven to be absolutely incompetent and disorganized on numerous occasions, ranging from letting individual Republic member worlds be blockaded by a corpo to trying and making peace with the Vong.

Palpatine could win, Thrawn could win, but everything else is sidewalk pizza.

 

[Aldarion]

Unless you are jacking 40k through the roof, any conquest is basically on SW's sufferance.

The SW industrial and military base, in any of the listed time periods, is simply orders of magnitude beyond anything that the 40k forces can hope to match.

Based on what? Even in the EU, battles normally aren't that big. Thrawn wages a campaign against the New Republic with a dozen star destroyers, and 200 ships of the Katana fleet were supposed to be a massive advantage, despite six of them being required just to stalemate a single Star Destroyer.

In canon, Kaminoans say to Obi-Wan that there are 100 000 units ready with one million on the way. Now, a "unit" could be either a clone trooper or an infantry square seen here, each of which has 90 soldiers. This mean that, at absolute most, clone army has 100 million soldiers. So minimum-size clone army would be basically a rounding error for the Imperium, maximum-size one would be... OK, a bit larger.

Now, it is true that we are talking Ultramar only here. But Ultramar still has an entire Space Marine legion, Ultramar Auxillia (who are nearly equivalent to the Imperial Guard) and significant naval force. Absolutely nothing we had seen in Star Wars canon suggests that they have what it would take to conquer the Ultramar, or stop Guilliman from conquering at least some sectors.

The invaders also have to contend with the Force. 40k precognition and general warp abilities are a joke next to what Force users wield until and unless you hit the extreme high end for 40k.

And what do Force users wield? I have seen nothing that suggests they would be able to even match psykers, unless you go into high-level EU stuff.

So what you said is true for Legends at most.

I mean seriously, Droids are AI and any attempt to not go total war against them will lose him, instantly, more than 99% of his mechanicum support.

Nah. Mechanicum was more than happy to play with AI, especially pre-Heresy. I mean, you do know that nearly everything in Imperium has some form of AI?

Disney canon is a joke written by individuals with raging hateboners for Star Wars.

Even ignoring that, you still have tiny little things like ten thousand Star Destroyers, populations that dwarf Warhammer, and multiple Death Stars.

The DS 2 alone is more military tonnage than every single human flagged vessel sourced in all of Warhammer lore. By at least an order of magnitude. And it was built in a handful of years.

And in Lucas canon, we have fleets of dozens to hundreds of ships at most, and galaxy-spanning war waged by an army that is half a billion strong at most and more likely actually only million-odd troops. Imperium as a whole has trillions of troops.

Ultramar itself is a little more difficult to gauge, but in this scenario we still have 250 000 Space Marines, millions or maybe billions of Ultramar Auxillia (modern day Earth has 20 million active-duty military, so 500 worlds would have 10 billion troops in total), and at least six star fortresses that are not that far off the Death Star in terms of size and firepower. In fact, they are very likely superior in both.

The Ramilies-class star fort Imperial Heart was a weapon built on the scale of a planetary moon, a behemoth of plasteel and ceramite. Six months earlier, wheezing tugs had dragged it from its ancient orbit about Holy Terra and pushed it through the hectic space lanes, past the gantry locks, scaffold-rigs and ore-barges of Mars, and out to Mandeville point 4HA.

Also, ten thousand Star Destroyers are a joke compared to Imperium. Your average ISD is 1600 meters long, which is the size of an Escort used by the Imperium. A single sector in Imperium is a cube of volume of 200 light years, encompassing 80 worlds, and has 50-75 ships of Escort size and larger, at least one of which will be a battleship. Imperium as a whole has a total of 1 million worlds - so about the same size as the canon Galactic Empire - which means that there are 12 500 sectors and a total of 625 000 ships that are at least as large as Imperial Star Destroyer.

Ten thousand Star Destroyers is hardly impressive against that. Luckily for them, that is not what they are up against here. I do not know how large Ultramarines fleet was, but from what I have found, Ultramarines Chapter fleet was 3 battle barges, 8 strike cruisers and cca 25 frigates. Since Chapter is 1 000 marines, and Ultramarines as a legion had 250 000 Space Marines, total numbers for the Ultramar fleet should be 750 battle barges, 2 000 strike cruisers and 5 000+ frigates. So "only" 8 000 warships of ISD size and above. Against 10 000 Star Destroyers... I like those odds. Even 25 000 Imperial Star Destroyers should not be at the "oh fuck, we cannot handle this" level.

Now for Death Stars, we do not know how long it took to build them or what kind of resource investment they represented for the Empire, but it is clear that for whatever reason ability to build the Death Star does not correspond to ability to build actual ships.

And if you ignore the truly idiotic SW canon, every SW capital ship is qualified to carry out a Base Delta Zero in a period of hours.

First, firepower numbers were set by the OP. So this is meaningless.

Second, that BDZ is bullshit on multiple levels even in the EU. Most of the time, per-shot firepower of ISD ranges from "modern-day artillery" to "city-busting".

Not to mention that portrayal of BDZ itself usually (not always, but most of the time) doesn't come close to an Exterminatus, with most portrayals falling again into kilotons-per-shot range and achieving basically what humanity today could achieve with existing nuclear weapons arsenal. In fact, when we get the definition of BDZ:

"Sir, what about bombardment? Is there a stage for that?"
"Blasting a planet from orbit is easy -- you don't need me to tell you how to do that. Limited orbital strikes would occur during the invasion stage. Just hope you are never given a Base Delta Zero order, lieutenant. Ah, yes, another question?"
"Sir, what's the Base Delta Zero order?"
"Base Delta Zero is the Imperial code order to destroy all population centres and resources, including industry, natural resources and cities. All other Imperial codes are subject to change, as you well know, but this code is always the same to prevent any confusion when the order is given. Base Delta Zero is rarely issued. ...."
-- "A World to Conquer"

That is absolutely nowhere comparable to your typical portrayal of the Exterminatus.

 

[Battlegrinder]

The invaders also have to contend with the Force. 40k precognition and general warp abilities are a joke next to what Force users wield until and unless you hit the extreme high end for 40k.

Unless a major Force power decides that it is in their interests to fuck with Force precognition then both the Jedi and the Sith are going to know about every attack, every warp transit, and every army movement essentially before it happens.

Neither Jedi nor Sith have ever benefited from this sort of foresight at any point in any canonical work, nor in any of the legends material that I am familiar with. Even the short term precognition that they indisputably do possess is far from foolproof, given how often we see them taken by surprise and killed. Fallen Order comes to mind as a recent example, where we had 4 force users in the cast and not one of them realized Vader was going to show up and try to kill them (or actually kill them, in one case).

And girlyman, for all of his ability, will still die if the continent he is on gets glassed or the planet blown up. Will it happen the first time? Or the second? Or the third? No. But eventually he will prove himself enough of an annoyance for the SW factions to just resort to BDZ to remove him from the equation.

.....and? It's not as if Guiliman is uniquely vulnerable to getting bombarded from orbit, that could happen to anyone.

The only point to be made about assassination is that unlike the Empire, Republic, CIS, New Republic, etc, is that the ultramarine aren't dependent on Guiliman to stay together, if he falls his subordinates will take his place. That is not true for many of his opponents, who cannot easily recover from an equivalent decapitation strike.....and are far more vulnerable to it.

 

[Agent23]

Neither Jedi nor Sith have ever benefited from this sort of foresight at any point in any canonical work, nor in any of the legends material that I am familiar with. Even the short term precognition that they indisputably do possess is far from foolproof, given how often we see them taken by surprise and killed. Fallen Order comes to mind as a recent example, where we had 4 force users in the cast and not one of them realized Vader was going to show up and try to kill them (or actually kill them, in one case).

Yup, Jedi precog is not what it is cracked up to be.
In a tactical battle it can be occasionally useful, like Luke's escapades, but it is rarely concrete, it is vague as all hell.

 

[Carrot of Truth]

Pretty sure a large military under the command of a Primarch could pull off a conquest of cannon SW and even give the EU a run the Primarch being Girlyman makes it far easier considering he tolerates xeno scum.