Why are primarch threads so comfy, lads?

Why are primarch threads so comfy, lads?

Lorgar best boy.

Other urls found in this thread:

bolterandchainsword.com/heresy/thedornianheresy.pdf
wh40k.lexicanum.com/wiki/Thunder_Warriors
wh40k.lexicanum.com/wiki/Two_unknown_legions
twitter.com/AnonBabble

Why does Magnus have two eyes there? And why are they not in numbered order?

Because skub wars are the best

How hasn't chaos won? Does the Imperium actually have anything that could stop a traitor Primarch? A titan maybe? but they have those too.

Isn't the deal with the primarchs that they're all daemonified and can't stay in the materium for too long? Angron did a bunch of shit but got banished or something

oh, fuck. Maybe, haven't kept up to date with fluff in years and have forgotten most of the shit I once knew.

>Does the Imperium actually have anything that could stop a traitor Primarch?
Gay Knights.

>How hasn't chaos won?
No-one appart from Abaddon really gives a shit to try. Becoming a Demon Primarch seems to sap away their will to act outside the great game.

Apart from Magnus who's still mad lol.

>primarch threads
>comfy
I'd really like to know your definition of comfy

>www facebook com/WarhammerTVteam/videos/284803978581254/

So lets discuss how Magnus will job against the SW again. I dont even remember him being involved in the first book?

Because it's really inspiring to watch people have well thought out, sensible arguments about which of these immortal man-children had the moral high ground

Don't daemons have to stay longer in the warp to reform the more powerful they are?

I mean it would explain why the ones that have been beat before haven't shown up again, and maybe the ones that never did anything are waiting for an actually crucial point to attack.

Dorn here to tell those damn hippies; Konrad, Fulgrim, Magnus, and that Daddy's boy Sanguinius to get a haircut. High and tight is the true space marine way.

>Implying bald isn't best.

Primarchs were anything but comfy

Lost Primarch threads are even comfier.

Baldness is clearly the path to chaos Horus
You're in I know you sport a real man's haircut.

I don't really see Ferrus as APD. He's definitely not right in the head, but he's not manipulative or impulsive. He's just cold and uncaring to an inhuman degree.

Lets get this shit started.

>Lorgar
>singlehandedly kicked off the Heresy that brought the Imperium to its knees
>Low Tier

Is this combat rating? Because I always feel like Ferrus is ranked way too low. He was beating Fulgrim until Fulgrim went full daemon and Fulgrim was supposed to be the best duelist.

Where does he fall?

>didn't successfully conquer his world
In Trash-Tier with Angron.

>Lorgar
>Every not being Low Tier
Nah m8.

Is this combat rating/potential. I could see an argument for Ferrus to move up or swap with Khan.

Where does he fall?
Mid tier.

Rogal Dorn approved.

I can get behind this.

Except top-knots are the most warhammer you can be.

daemon primarchs > not daemon primarchs, at least visually
prove me wrong

Kek. Nice work user.

Lets compare shall we?

Cant wait to see what FW do with the guy.

And Russ of course for comparison.

terrible, you should feel bad

>beat the stronkest bloodthirster in the fucking warp

>meanwhile mutant hawkboy could beat a rank and file bloodthrister who BTFO an entire company and him to a coma

Dunno, it's a mixed bag.

Greeting Guardsmen,

Today we have another history lesson for you.

You may have heard of the Burning of Prospero. As with many events of that tumultuous time deep in our history, it can be tricky to unpick the facts from the rumours and conjecture*. Fear not, we at the Regimental Standard are here to bring you the (Ecclesiarchy approved) story of really happened.
The Thousand Sons, as you may be aware, were one of eighteen** Legions, gifted with the task of reuniting the scattered worlds of man to form the united Imperium – the infallible Emperor’s chosen destiny for the galaxy. However, unlike the noble Space Marines of the Ultramarines, Imperial Fists, Blood Angels and other loyal Legions, some Legions – including the Thousand Sons – squandered this gift. Magnus’ Legion were more concerned with the accumulation of heretical texts and knowledge, even going so far as to shield heretical cultures from the true light of Imperial compliance.

Under the malign guidance of their cold-hearted, rule-disregarding, cyclopean primarch, the Thousand Sons gathered a wealth of blasphemous tomes and scripts in the libraries of their home world, Prospero. As you can imagine, this world was a despicable place, its cities wretched cesspools of corruption and villainy, quite unlike the civilised hives of modern-day Imperial worlds.

This seeking of blasphemous knowledge would inevitably lead to their corruption, and damnation beckoned! Something had to be done.

The Emperor*** sent the Space Wolves, noble and civilised defenders of the Imperium, to put a halt to the Thousand Sons blasphemy before it was too late. Little did they know… they were already too late.****

Upon peacefully landing upon Prospero, the Space Wolves were fired upon by fell magics, conjured by the now-unsalvageably***** corrupted warriors of the Thousand Sons Legion.

Luckily, the Wolf King Leman Russ anticipated his brother’s treachery, and his warriors were accompanied by the legendary Sisters of Silence, warriors whose love of the Emperor was so strong, it was able to protect them from the ravages of the enemy’s sorceries (not unlike how your own faith in the Emperor can protect you from similar threats).
The loyal Imperial forces quickly, and with astonishingly few casualties, broke the forces of the traitors, driving them back to a final battleground. There, the mighty Leman Russ fought his deluded, raving brother, and broke Magnus’ back in single combat, forever banishing his foul magics from the galaxy.

– Another resounding victory for the Imperium!

Now, there are some who claim that in those last moments, the Thousand Sons Legion somehow escaped Imperial justice. We can assure you this is not the case. No crimson warrior bearing the symbol of the XV Legion has been seen in the Imperium since the events of Prospero, and we can therefore reliably confirm that they were all slain.

That concludes your history lesson for this week.

If you have any questions regarding the use of sorcerous powers, or the acquisition of blasphemous texts, please direct your questions to your Regimental Commissar.

Thought for the Day:
‘All your works turn to ash and dust if they do not serve the Emperor.’

*All conjecture is Heresy
** AND ONLY 18
***Blessed be His name, holy protector and light of humanity
****These were more innocent times. We now know, of course, that it is always too late to save those corrupted by dark powers. Only death and flame bring purity.
***** The Administratum assures us this is definitely (probably) a real word.
How can vile sorcerorfaggots ever recover?

How do you know Mortarian needs a haircut?

>Primarch thread
Obligatory

...

old magnus with beard > new magnus
new angron with cord dreadlocks > old angron
prove me wring

A beard like that is not fitting for a genetically enhanced magical philosopher king such as Magnus.

>Magnus the Red not being the Primach of the Neckbeards

I'd argue that Perturabo is a better neckbeard Primarch. He's as much of a nerd as Magnus with his love for knowledge but he also plays warhammer 40k table top. He's Veeky Forums incarnate.

...

>How can vile sorcerorfaggots ever recover?
Yes I agree.
By the way fellow loyalist there's no need to check out those warp storms around Fenris. I'm sure everything will go JUST AS PLANNED

Her body proportions make even less sense than a space marine's when she's in that armor.

That looks like a real shit drawing. Normally the pauldrons just look like they're resting on top of her shoulders, rather than whatever the fuck that is.

Most redundant Primarch coming through.

Whilst everyone else was out winning new world for the Imperium Russ was stuck trying to group together a culture that even he hated.

The 'Emperor's Executioners' instead focused on talking themselves up and policing the other legions, a task they failed miserably at. When the time did come for them to actually do their job they were mislead by Horus making their biggest act in the Horus Heresy a disaster for the Imperium.

Not as savage as Angron, not as loyal as Dorn, doesnt hate psykers as much as Mort, noble warrior king done better by Khan. I guess they have more wolf references then Luna Wolves so yay for them I guess?

Not the worst of the Primrachs, but truly the most redundant.

>Not the worst of the Primrachs
what did he mean by this

>what did he mean by this
Angron and Curze should have been put down.

Angron should have been helped (if even by force as his mind wasn't his own) by Magnus/Emps to remove (or at least lessen) the nail's effects.
Curze just needed more time with dad so he wouldn't turn out like a fuckwit from his visions of happenings.

You know who SHOULD be put down though? Lorgar. Fucking Lorgar. Such a piece of shit bitch ass primarch...

Fixed it up for you.

>rougue gay is number 1
pic related

This is why Dornfags shouldnt be allowed to make decisions.

>You know who SHOULD be put down though? Lorgar. Fucking Lorgar. Such a piece of shit bitch ass primarch...

All he ever wanted was the truth, user. The Emperor should have made him the Imperium's chief propagandist a la Goebbels and refocused his zealotry into the Imperial Truth. Things really didn't need to go the way they did.

>You know who SHOULD be put down though? Lorgar.
He almost was until he got back on that Crusade hype.

>Angron should have been helped
Angron was found so late in the GC that Emps just used what he had. Angron was obviously a failure.

>Curze just needed more time with dad
Nah guy wasnt right in the head. Have him locked up or put down.

...

If people read "The Dornian Heresy" I feel like there would be less arguing about primarchs and who is the 'best' one just because people would have a better head-canon towards them.

do tell

bolterandchainsword.com/heresy/thedornianheresy.pdf
It's probably the only good fanfiction besides "The Shape of the Nightmare to Come." It's an alternate telling of the Horus Heresy in which all loyalist Primarchs fall while the Chaos Primarchs remain loyal to the Emperor.
I think it does an excellent job of fleshing out the nuances of several of the primarchs - espeically in ways where most people would gloss over.

>He has stats from White Dwarf that makes him a 500 point walking rapemachine who makes Abaddon the Despoiler and Mephiston look like total pussies, but you have to get him a bodyguard of at least 2-12 bloodthirsters, which effectively racks up his point cost to over 1300 at the least. But with his mandatory bloodthirster bodyguard he can even kill An'ggrath, the biggest and baddest bloodthirster of them all.

You do the math.

One pollutes himself by wearing Chaos-tainted armor, and the other has polluted herself with two different types of Xenos DNA, on top of being turned female during the voyage through the Warp?

Yeah, I can see why the Emperor would have had them purged, and all memories of them erased.

>T6, W5, Sv 4+/5++
Gets shot to death by an AdMech War Convocation-tier

Because strong male authority figures make you feel safe.

He was bald and foolish.

Mortarion looks so cool

He's obviously hiding some sort of shameful haircut under that hood....maybe he has a mullet

Makes sense, doesn't it? They got transported to parallel materiums through the Warp. Now they're considered too corrupted and too out-of-reach to even consider rescuing or redeeming them. Best to erase them entirely.

On that note, what does Veeky Forums think their stats are?

It's a nice occasion to write about some interpretative work I tried regarding Legions and their Primarch. I wondered what lost legion would be like and figured that every Primarch and Legion was made for purpose, with idea in mind. It is clear espescially when looking at how legion was before they met their Primarch. Starting from the first ones I belive they are as follows:

I - Lion - Dark Angels - First Legion, first Primarch made, first space marines. Basic, template Space Marines. Versatile, stable, reasonably loyal (we are talking pre-heresy) but not excelling in any particular way of warfare. Their Primarch mirrors it, as he is everything that was needed from "basic" Primarch, great general and strategist, but lacking in many other aspects (amongs them his "autism")

II - No information

III - Fulgrim - Emperors Children - They were Emperors attempt at "improving" basic Space Marine. Make them not only great soldiers but wonderful human, artistans, scientists. They were designed to excell in any human endeavour. They were to be "warrior-poets", embodiments of human perfection, ideals to strife for. Unlucky Emps fucked them up which resulted in their "cancer" that decimated pre-Fulgrim Legion and instilled in them pathological-perfectionism.

IV - Perturabo - Iron Warriors - Another "improvement" Legion, but where III was to be better human beings, IV were to be better warriors. It might seem that their was the specialisation to siege warfare and garrisons but I would argue that this is just the after-effect of their true purpose. They were just the harder hitting force so it was only natural that they were used on the hardest obstacles, ones that needed long sieges to crush. Sadly "improvements" resulted also in deepening flaws observable in their "older brothers", they were even more autistic and dehumanized.

V - Jaghatai Khan - White Scars - First of "specialized" legions. They were to be Vanguard force of Great Crusade, "Scouts", always forward from the main force of Imperium. Possibly also Emperor planned them for Webway wars (which I would argue Emperor wanted to wage after GC)

VI - Leman Russ - Space Wolves - Possibly at this point Emperor realised he would need force to keep in check his own soldiers. This is how Space Wolves began, they were truly concived as the Emperors executioners, internal police force. To do that they had to be powerful and fiercely loyal which Emperor tried to achieve by spliting their genome with Canine genes, probably trying to instill in them genetci loyality of the dogs. There are rumors that Leman Russ were part of destroying two lost legions and he boasted that he could defeat every Primarch despite Horus in real battle, which might be true (I won't dwell upon Russ-Lion or Russ-Angron matches)

VII - Rogal Dorn - Imperial Fists - They pretty much served their purpose before and in the Horus Heresy. While original Astartes were crusader, conquerors, Imperial Fists were to be defenders, castellans of created Empire. They were highly loyal, had a knack bout constructing defenses and zealous as to never abbadon what they were defending. Black Templars embody their zealotry side.

VIII - Konrad Curze - Night Lords - They were to be police of Empire, force used against rebells. Ones that were used to punish those that broke their oaths to the emperor. They were to be bat that deters anyone who would think about mutiny. I would argue that Konrads visions were one ot the tools that Emperor wanted to give this force to better serve their purpose: they were to be able to prophecy/sense who is likely to rebell and also to see how best to punish them as to what punishment would be most severe. This looks like a new approach by the Emp, as he maybe started to feel confident in his ability to create Primarchs (he fucked up this time)

cross posting for the glory of the primarchs

I feel the Iron Warriors would've been builders in a post war Imperium. In the HH novel about Perturabo, they build a giant amphitheater in day or something like that. They also weren't even being directed by Perturabo. If I recall correctly they were being directed by Forrix who was just a normal Space Marine and who I think embodies the fourth legion best.

IX - Sanguinius - Blood Angels - We must look at them by the prism of the previous Legion. Emperor geting comfortable in creating SM, learnt few tricks and started to try more esoteric ways (he gave Curze ability for Prophetic Visions). It is possible that they were to be dedicated Shock Troops but after examining Sanguinius (and how great he turned out to be) I would say that Emperor tried creating "better SM" ones more, using all the knowledge from the previous legions. One of the argument for that would be fact that Sanguinius had prophetic visions simillar to that of Konrad Curze. On the surface it seems like Emps succeded in creating "best SM" but actually he fucked up and Blood Angels turned out flawed (red thirst) and their "spiritual/psychic" link to their Primarch (which in my opinion is another of Emp designs) caused Black Rage. (I have alternative interpretation fo Blood Angles more in line with them being Shock Troops but that maybe later)

X - Ferrus Manus - Iron Hands - They were created to have Iron in their Hands... Another "specialised" Legion. Mobile Warfare, affinity to machines, perhaps instrumental if Emps would ever want to purge Cult Mechanicus.

XI - No data

XII - Angron - World Eaters - Again, two interpretions are possible. Even before Angron and Nails they were known for their fury and resolve. It may be that they were to be designated Shock Troops. But there may be more nefarious purpose to them: to be "improved" Space Wolves, Astartes killing (arguments for that would be: they were used to destroy rebelious thunder warriors, for the most part of GC Emps kept them in the backlines, as if they waited for the occasion to act on their real purpose, possibly relations to Minotaurs, strange relations with Leman Russ/Space Wolves).

I was thinking along those lines too at the start. It would line perfectly with the grudge that Perturabo holded against Rogal Dorn and the fact that it was shown many times that Pert wanted only to create something of his own. But it would then mean that there are 2 legions with the same purpose: Iron Warriors and Imperial Fists. But maybe Iron Warriors were to be builders of the Empire, while Imperial Fists were to be personal Emperors bodyguards.

Does anyone have the link or source of the World Eaters killing thunder warriors?

Is there a reason why a Vindicate rifle to the head wouldn't do it?

I'm guessing it's something hilariously absurd, like their skulls being as strong as a three meter thick plate of steel. Or pic related.

wh40k.lexicanum.com/wiki/Thunder_Warriors
It is presumably from Horus Heresy Book One: Betrayal Page 27, 85

For the record the Sons of Magnus are always welcome in the libraries of Pnakotus.

After a small break I come back!

XIII - Roboute Guilliman - Ultramarines - They are the Empire builders as in, not architects, but logisticians and planners. With them begins SM that were not soldiers first but more servants and helpers of emperor in many other of his endeavors linked with Imperium. Their main traits are highly visible in a way they concquered worlds in creation of Ultramar Realm, Empire Secundus and Codex Astrates (all the criticism against it is sound: it limits the strength of SM, but what the critics don't see, the purpose of CA is NOT to make better SM organization. Purpose of CA is to not allow for a single greatest threat to empire that Roboute Guilliman knew of to arise again: traitor Legion.)

XIV - Mortarion - Death Guard - They might be just chemical warfare specialists, maybe astartes designed for toughest environments. But I propose something different. Judging by Mortarion fierce hatred for psykers and anything warp-connected I would argue that XIV Legion is anti-psyker force. It even may be that Emperor created them having the next Legion in mind (Thousand Sons). Emperor wanted force able and willing to fight any and all psykers and able to whistand anything said psykers could throw at them.

XV - Magnus - Thousand Sons - Just now after creating XIV legions emperor embark on the hard quest to create post-humans that would have direct control over warp. I think Thousand Sons are easiest to understand what they are. There is a lot to say about the subtelities of them and Emperors plan towards them (why Nicaea, why emps was so secretive about his work and warp, why, why, why). Answer to Thousand Sons questions is an answer about what Emperor knew and wanted to do but it is topic long in itself.

XVI - Horus - Luna Wolves - It's hard to distill what was the exact purpose of Horus because of the fact that he grew so close to emperor and knowing what he would become. But I would concentrate on one thing specially. Horus was diplomat, mediator. If he was orginally designed to be used amongst empire or for allies and towards conquered is murky. I belive both. This gift made him naturally predisponed to be Warmaster as he was able to sway and control his brothers and myriards of people in GC but we can see he lacked many qualities. (On the short note if Primarch were never scattered I belive that designed pick at Warmaster was Lion who would however be outclassed by Sanguinius. Sanguinius would be Warmaster with Horus as his "Prime Minister").

XVII - Lorgar - Word Bearers - As Horus was diplomat, Lorgar was preacher. He had great purpose in the greater scheme of things. He was to be prime propagandist for the Imperial Truth and he was to teach what Emperor wanted to be taught. However he was corupted from the young age by religious zealotry. I think if not for the Scatering, if Lorgar grew up by Emperors side and could understand and appreciate his vision, he would be greatest defender of Empire of Man. It was fault of his adoptive home that he searched for "Gods" instead of "Ideals of Humanity".

XVIII - Vulcan - Salamanders - They are the defenders of humanity. They were to be force protecting people. Not crusaders, not defenders, not conqueros but protectors. Heroes. It is seen in their deployment during Great Crusade before Vulkan was discovered (they were almost always fragmented like "modern" chapters are, combating emerging threats. It is still very visible trait in them with their empathy toward simple humans, connection to their families and civilians. Emperor wanted them to be empathetic to always stay vigillant against threats that combating which was less glorious, less honorable but most horrible against civilians.

XIX - Corvus Corax - Raven Guard - It is perhaps easiest to show their purpose by comparing them to Vth legion White Scar. While WS were to be Vanguard. Point of the Spear in the Great Crusade, fast nimble, atacking from many directions but hard, steel and honest weapon that is able to smash enemies on it's own and always followed by full strength of Imperium. Raven Guard was different, RG was to be arrow from the back ranks, hidden scout cavalery in the forest, cossacs far into the enemy territory distrupting their supply lines and destroying infrastructure, also counter force against such practices. They were covert opperatives, kommandos, sabotages, planners of bigger war picture.

XX - Alpharius/Omegon - Alpha Legion - While Raven Guard are the arrow and short sword, Alpha Legion is the dagger under the cloak, poison in the well. They are assasing, they are gorilla warfare specialists. They are to instigate rebellions, they are to hunt dissidents. I belive eventually Emperor wanted them to replace Officio Assasinorum and be much more. They were to be his Secret Service, spies, planners, needles. Also I belive that the whole "twin thing" is by design by Emp. A and O are not cooperating and twins and "one soul in two bodies" this is lie and propaganda (as should be expected from XX) they are exacly opposite. They were made to keep tabs on each other because Emp knew what would happen if the force like that acted unchecked and unmonitored. Second possible reason there were twins is that Scatering occured as Emp just finished XX legions Primarch and after the ordeal which possibly destroyed labolatories from Dark Age Emperor needed to create Primarch he was left with enough juice and infrastructure to create one more exact copy of the last one he did.

Literally weaker than a single Riptide, holy shit lol.

desu dude there's very little insight in your "interpetations". When you're not restating the widely accepted primary attributes of the legions and their Primarchs, you're pointing out well known secondary attributes.

You're basically just writing a summary of the Legions and their Primarchs. Your personal interpretation doesn't even enter into it.

I'm sorry that you've wasted your time.

>gorilla warfare

So you agree with everything I wrote? That's great and I agree it's basic summary, just to lay ground for the interpretative work of Emperor and Great Crusade. Also my point was to search what obvious roles were not incorporated in this so that we could extrapolate the character of the Lost Primarchs. II could be first attempt at making better Space Marines, XI is more tricky. What could their purpose be?

Angron is the best Primarch! Angron actually leaves the Eye of Terror to skull fuck the Imperium until a host of millions of Imperials manages to send him back with the help of industrial strength plot armored Grey Knights and even then he kills a hundred of them including their commander with his bare hands.

What have the other Primachs done?

Clearly one of them was made to kill daemons. The Emperor knew of Chaos & knew he had to fight them.

>They were created to have Iron in their Hands
No.
Ferrus hated the idea of relying too heavily on technology augmentations and was vehemently against the use of bionics in his legion. The attitude the 40k Iron Hands chapters have stems from Ferrus dying and analysis as to why he died (movives, goals etc).

Other than that I like your thoughts on the primarchs.

And the other was made to kill xenos. The Emperor knew how powerful some races were against fledgling humanity & knew he had to fight them.

Both were sent out and then erased from memory so no one would know of Chaos nor the threat that xenos posed. Also, to keep anyone from distracting his wayward super-children from their primary function.

I like it.

holy shit bro, does your elitism keep you warm at night? That's a lot of lore and reading he just summarized very well for the layman.

>one was made to kill daemons
>one was made to kill xenos
>Doomguy and Samus Aran
This makes too much sense...
If only they had the physicals to back it up I think this fan theory could have some traction

kondrad wasnt sadistic, he was nihilist. his ultimate dream was to topple the imperium because it was hypocritical (preaching ideals while waging war in the name of a power hungry emperor)

No doubt, Dorn was the most soldierly out of all of the primarchs.

It was a joke about their name-obsession with Iron and Hands. But that is actually a great and valid argument espescially toward the Iron Hands being planned replacment for Cult Mechanicus. Emperor needed post-humans who would be able to understand and comprehend ridiculously advanced tech of 30 millenium but also wanted them to not be batshit crazy flesh-haters that Mechanicum are. He wanted them to be balanced so he tried to instill in them profound love and respect to human body as in Mannus monologue about him reshaping them after heresy. But because of what happened in heresy this subtle lesson was completly lost to them, very tragic.

Easy. The Emperor grew his lost children to largely resemble normal people, that way no one would pick up on them being primarchs. That's why they're so small compared to their siblings.

I meant physicals like strength/speed etc. Doomguy and Samus, while pretty fucking cool, simply don't have anything in their lore that would indicate anything stronger than a standard space marine.

If you go by certain texts, Samus grew up on Zebes, which supposedly has 800x normal gravity. Meaning, to move around normally, she has to have at least 800x normal strength. And Doomguy seems to get more powerful the more demons ge slays, so theoretically his strength has no upward limit. That seems like it could be approaching Primarch territory.

>800x normal gravit
This was printed once and never mentioned again and it doesn't match up with any cut-scenes we see Samus in following any game she has ever been in ever.
I put it in the same catagory as the time a gaurdsman killed a chaos marine according to one of the Black Library's books while in every other book Chaos Marines can typically shred through entire gaurdsman regiments

Who in the world is that in the middle at the top

>That's a lot of lore and reading he just summarized very well for the layman.
and yet the point he was trying to make is that the primarchs were somehow created for specific reasons.
those reasons ended up being the very same things the primarchs are already known for. this is just wrong because most of the characteristics of the primarchs were due to their upbringing and not their genetics.

rob girlyman

Like I said, it's dubious at best, since Metroid canon conflicts with itself. But it's something.

Also, at this point the suit is just an extension of her body, so you could argue that her in-suit strength is her natural strength. Perhaps the Emperor, trying to hide their presence, made the lost two primarchs of human strength, but landed them in situations so they would grow to be more. And by the time they had grown into their strength, they'd bee too iron clad for chaos to corrupt them.

In other wordas, all according to Emperor's keikaku for once

Roboute Guilliman

I like this whole theory, one to combat chaos, one to combat xenos, elegant. But if we want to be canon, both Legion had separate tragedies that made them be purged by Emperor and both occasions were remembered with fear and sadness by other Primarchs.

Here is nice compedium of information:
wh40k.lexicanum.com/wiki/Two_unknown_legions

Brouzouf man would be better