The LOST LEGIONS & PRIMARCHS of the HORUS HERESY | Legions II & XI: Origins & Lore

In the universe of Warhammer 40,000, the Emperor created twenty Primarchs and twenty Space Marine Legions to unify the galaxy. But by the time of the Horus Heresy, only 18 remained. What happened to the two lost legions and their primarchs, the 'forgotten' and the 'purged'? In this video, I take a look at the evidence.
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[@rickpriestley4569]

Interesting piece and lot's of interesting and credible theories there! I have no more idea than anyone else what the truth of the matter is, of course. The backstory has certainly evolved and acquired some mass of detail since I first drew up that list of Space Marine Chapters and their Primarchs. I'm not really familiar with a lot of that material either, but it's nice to know that the spirit of the thing has been preserved and even nurtured. I will make just one observation - and it's about the intent of the missing legions - where I think GW have perhaps taken a slightly different tack than I had in mind. Not that this matters of course, and I appreciate that in creating a series of books about the Heresy a lot of things I always intended to be unknowable or semi-mythical had to be addressed directly; something I could never have foreseen when I wrote Rogue Trader. The intent is this: that the removal of records and obliteration of the memory of these Lost Legions was not a punishment but a reward - rather than being purged they were being absolved - and this was based on the assumption they had done something utterly terrible (naturally!) but then done something equally positive to earn redemption. Or think of it as a stain that cannot be erased except by extinction. The Chaos Chapters are unforgiven - out and out bad guys - but the Lost Legions, whatever their deeds, have been forgiven and the stain upon their reputation erased with their memory. At least that was the idea... but times change don't they ;)

[@ArbitorIan]

Hi Rick! Thanks for the comment and the secret stash of lost data! 😂 Times do change, but I think that sounds like a great way to handle them. That they did something terrible and then earned the right for it to be forgotten, contrasted with Horus' traitors who never attempted to atone. I do think a bit of your original idea, or some sense of it, is still in there somewhere. There's still this sorrow and sense of loss every time they're mentioned that's quite different from the response to the traitor legions. But after 30 years of content building and expanding, I'm impressed that it's still a mystery. There must have been so many author requests to do something with them that have been refused over the years to preserve that!

[@escudoturbo]

I believe this is known as the 'Word of God'

[@fredslipknot9]

Hi Mr Priestley! Just stopping by to thank you for your work, making such a big contribution to my life. Warhammer, 40k but especially Fantasy (I still have the 6th edition Lizardmen codex I originally got twenty years ago!) and it means a lot to me. People such as yourself make a far greater & better impact upon the world than any politician or general, and one that has personally impacted me very deeply.

[@oatlord]

!!!! A famous person

[@retroriven9740]

This comment needs to be pinned!

[@NeroIML]

During the video I had the idea that one or both of the lost primarchs landed on worlds where humans and xenos coexisted peacefully and that they were unable to accept or even resisted parts of the great crusade. Instead of being corrupted by an outside force like Chaos they were just not compatible with the Emperor's vision of the future of humanity. Maybe it came to a head during the Rangdan war and one of them refused orders or even surrendered to the Rangda in order to try and find a diplomatic solution? A worse crime than falling to chaos; being a hippie. (or at least, believing in coexistence and peace rather than conquest)

[@MisterTingles]

thought the same thing, in a universe of unending war who would possibly be less conscionable than an apex warrior advertising for peace...

[@starofcctv94]

My personal favourite. Falling to chaos is is useful propaganda to why the imperium has to exist. Whereas the belief that another way is possible is so dangerous it has to be wiped from everyone's memory.

[@thealleycatuk]

Yeah, in my headcanon one of the lost primarchs walked away.

[@justincoates4582]

@@starofcctv94 yep. The idea that you have a choice other than the emperor or Chaos is truly a threat to the Imperium.

[@nekrataali]

I also subscribe to this canon, because "memory wipe" doesn't make sense. If the Emperor was capable of wiping away memories of primarchs, why wouldn't he wipe the traitors' memories and brainwash them back to being loyal? Why allow some of them to have the traumatic origins they had instead of wiping their memories when they were first discovered, then planting false memories or simply lie? After the traitors turned to Chaos, why didn't the Ruinous Powers, Tzeench and Slaanesh in particular, unlock those memories? What better way to secure a traitor and oathbreaker's loyalties than reveal to them a truth that feeds into their desires or schemes? However, if the one or both of the lost primarchs were diplomatic with xenos (or worse: living among them), then it makes sense as to why the traitor legions continue to go along with the coverup. Chaos Space Marines still hate xenos just as much as the loyalists do. Even to a Chaos Space Marine, aligning yourself with aliens is abhorrent. It goes against the Primordial Truth of the galaxy belongs to humanity and humanity belongs to Chaos. If Chaos wins and destroys the Imperium, it will be looking to destroy Necrons, Orks, and Tyranids while enslaving the Eldar and T'au. Having some goody two shoes demi-god using diplomacy to co-exist with the alien puts a dent in both the plans of the Imperium and the Ruinous Powers.

[@CrimsonTemplar2]

40K lore is (in some ways) a masterclass on using unreliable narrators & loose plot threads to tantalize the reader rather than aggravate them. We’ll never really know what happened to II & XI, but this video is the best roundup of the relevant lore snippets from the various books I’ve found thus far (better even than Occulus Imperia’s video). Good job Ian!

[@thealleycatuk]

This. Nothing actually happened to those legions, they never existed. The guys who created the world wanted a couple of spots for people to create their own legions. When they then write the Heresy Series over a decade and many, many books though, it would be super odd if no reference was ever made. So authors get to have some fun with that but are never going to state a clear and definitive answer.

[@aaronmcgowan5769]

@miniaturemasterclass do you mean Rick Astley?

[@henryheavy8044]

No that’s just lazy

[@Inquisdrknss]

Following the cerebvore idea, the infected Primarch could be the ultimate carrier. Too strong to ever die from it, but subjected to a drive to spread their curse to every one, or to even allow the contagion to mutate to become an unstoppable threat

[@RSBurgener]

Here is something I have been able to theorize. The Emperor built redundancies into the Primarchs; Perturabo and Dorn being an example. Should one of them fail, the Imperium still had a siege master on duty. Yet Magnus the Red is the only Primarch with ultimate psyker abilities. So it stands right reason that one of the lost Primarchs was the other psyker. You can imagine what must've happened to get him and his legion eliminated.

[@brentbledsoe968]

I like the idea that the 2nd primarch basically told the emperor that he was a maniacal genocidal hypocrite. and then took some of his legion and other humans, mechanicus cohorts, etc etc.. and simply peaced out to go start another civilization a far ways away. The primarch realized that he could do something better than the imperium, realizing the Emperor, whatever he was wasn't doing this for the good of humanity but for himself.

[@stevekcole]

I always liked the idea that one of the lost Legion primarchs was assigned to be the void dragon's jailer on Mars and as no whisper of the void dragon could be allowed out that the primarch and his Legion were expunged from history but are still on Mars guarding their prisoner.

[@alejandrorp5160]

Follow-up: how cool would it be that the 2 missing primarchs never did anything wrong nor heretical, only they peeked beyond the veil: there can be a viable human society outside the Imperium and that's why they were executed/held in the Black Cells. Adding to that: what if that’s why most Primarchs can’t recall anything about them. Emps being Emps. What if Russ - we know how he values self reliance and independence and also how he only looks as being a savage- actually spared them - seeing some weight to their arguments but staying loyal to Emps- and let them go? What if he eventually left everything to check on them/ally with them to fight Chaos? Jaghatai's mindset and behaviour could also work there. Seems to me he only sided with the Imperium because Chaos is just not an option. Plus, what if the Alpha Legion's messy and fractured loyalties have to do with this (i.e. being anti-chaos, but also seeing the Imperium forwhat it is...)? That'd clear things for them, imo

[@TheCityofTownsville]

I've been "that guy" and have created a Legion - II Legion. They're, "The Lost". I had to do something with over 200+ Space Marines I've collected over the years. I gave them a Greek style background, the flagship is the Odyssean, and become lost in the Webway when the Emperor sends the Legion to collect data on the Eldar Webway. They were to wait for his arrival at the other side when he completed it. All info was 'lost' to hide the existence of the Legion when they went on their expedition. And, as we all know, the Emperor never did complete the task.

[@clanpsi]

This would actually have been an exceptional way of bringing them into present lore. The Fall of Cadia was... fine, I guess, but imagine if the tides of Chaos were stopped by one of the lost legions being released from the Webway as a result of the Great Rift. SO much better.

[@vohsbergh]

The Primarch Ulysses undertaking an Odyssey through the Warp to return, only to realize that 10,000 years have passed would be pretty cool

[@Firefalcon88]

I’m still learning the lore but this would be a great way to tie them in as the source of the Legion of the Damned. I think it would be cool if somehow being lost in the warp permanently altered them over time, merging with the warp presence/signature of the Emperor.

[@casualaccount9431]

@@clanpsi Better? Chaos flooding the Imperium is better!

[@comlitbeta7532]

Hey, never be ashamed of your OCs

[@retroriven9740]

There's a lot of videos on the Lost Primarchs but this is honestly the most detailed and to the point. You even backed it up with sources from the books! Excellent job!

[@stephenmcconville6288]

Agree entirely, this is the best summation I've seen thus far. Nicely done.

[@CynUnion-ji9uj]

I kinda want to interpret the Lost literally, The Lost, Lost not meaning KIA but literally missing, in a way that makes their return... unlikely. Like a damaged webway gate or bad warp trip.

[@michaelhowell2326]

I haven't ever thought of it that way but I do like the theory.

[@MWH12085]

One theory was The Lost was flung forward on time to M32 and was involved in The War of Yhe False Primarch

[@Anergyne]

"We lost the 2nd and 11th legions." "I'm sorry. How did they die?" "Die? No! We lost them and now we cannot find them! I don't suppose you've seen any Astartes legions in the Webway?" "I can't say that I have."

[@Illindi]

Another nice breakdown. It'd be interesting if one of them suddenly appears from the warp, chronology problem solved by warp being, well the warp.

[@Brennoprog]

I`m in the process of making a custom army and that is the thought process I have in mind. Like the Primarch and the Legion got stranded in the Warp and have been fighting daemons and whatnot the whole time until they were able to leave the Warp into the current millenium...

[@Deano3225]

I like the idea that one (or both) became increasingly pacifist or xenophillic as a result of the rangdan campaign, and saw the reality of the great crusade and what humans were going to do. Another I like is that one (or both) become so intrigued by the webway/warp that they just bugger off. Like if Magnus had even less restraint.

[@anotherzingbo]

Interestingly in the rulebook for 1989's Space Marine Epic game it says that the 3 chapters (this was before the first founding was commonly referred to as legions) wiped out at Isstvan were purged from Imperial records. The rulebook lists 8 loyal chapters (the current loyal legions, less the Raven Guard) and 9 traitor chapters (the current traitor legions) so at that point the 3 that fell at Isstvan were the lost chapters/legions. It seems to be that the number got changed to 2 when 2nd edition 40k was released and the details about the Isstvan massacre and when those legions were lost got added in later.

[@TheDarkTides]

I forgot which one of them was mentioned as "good guys" making the other "bad guys" but when it comes to 2nd and 11th, i believe one of the primarchs either willingly or via mind control joned the xenos rang'da and the other died trying to save him. When you think about it, there are plenty exaples where such thing could have happened to existing primarchs with close bond, like Ferrus and Fulgrim, Horus and Sanguinus, Leman and Lion (refering to their fistfight) and so on...

[@Jackalos1]

I like to think it was mind control. Primarchs being mind-controllable is extremely dangerous information so it makes sense for that information to be expunged.

[@BecauseOfDragons]

I still like the idea of Sigmar being one of the lost Primarchs. Fought against the Rangda but was so horribly wounded that only a portion of his "self" remained. Misdirected away from a journey home to Terra by the forces of Chaos, his stasis pod was sent through The Eye Of Terror and crash landed in The Old World where he was formed anew and become the demi-god of that world - when he left The Old World, walking back into the wastes, he was trying to find his way home. I always liked that as my own personal bit of lore for the Stormcast Eternals too - the way he'd always envisioned his warriors being but could never do it with the power he'd lost when coming to The Old World. Now, in the Mortal Realms, he has been able to perfect the process and fuse science with psychic powers and magic - crafting his own Angels Of Death. I know it's an old meme (but it still checks out) - and I'd love to do a little modelling project (when I have the guts to do so!) where I make that Lost Legion.

[@Crushanator1]

Yeah the old school Comet of Sigmar being a stand in for an infant Primarch atmospheric entry

[@BecauseOfDragons]

@@alfieingrouille1528 Ah but that's where my own head canon comes in :)

[@BecauseOfDragons]

@@alfieingrouille1528 That it happens as I mentioned in my first comment rather than how the story plays out officially. All for making your own stories and drawing fun from "what if?" scenarios. Don't have to stick to the official lore when you can make up what you like and have fun with it :)

[@nekrataali]

Another reason this idea checks out is because we know Age of Sigmar comes after Warhammer Fantasy. In WHFB, there's four chaos gods at the beginning, with kind-of-sort-of a fifth being Malal. By the End Times, The Great Horned Rat has ascended to being a full-fledged chaos god. And at the start of AoS, Slaanesh is imprisoned. This tells us quite a bit about the Great Game played by the Ruinous Powers. It means the chaos pantheon isn't set in stone and likely the different gods are trying to cast the others out. It also means they can reset the game by destroying the world. Since Slaanesh didn't exist at the start of 40k but did at the start of WHFB, this implies 40k takes place before WHFB. The universe in which 40k exists is destroyed, resulting in WHFB. Sigmar is either the Emperor himself or one of the primarchs. Just like how Karl Franz becomes Sigmar's avatar, Sigmar was some sort of avatar from a human deity in 40k. The horrifying implication of this is the chaos gods have been playing the Great Game for a very long time and have gone through multiple End Times. And no doubt they will continue playing long after the Age of Sigmar has passed.

[@BecauseOfDragons]

@@nekrataali Love it :D

[@KK-qm1mr]

On the topic of primarchs dying, I have a theory that all of them, not just Vulkan and Guilliman, are perpetuals, but not all in the same way. (I do think Horus is properly dead, though. Special circumstance.)

[@N0-1_H3r3]

The idea that the II and XI Primarchs "did something worse" than Horus doesn't really ring true to me: rather, Horus' betrayal was something so large that it *couldn't* be covered up in the aftermath of the Heresy. On the idea of the Rangda being part of the mystery... the Dark Angels were heavily involved in that conflict, and their Librarians are often shown to be skilled in telepathy and the extraction and manipulation of memory. Were the First Legion sent to combat the Rangda because their Librarius was more suited to fighting foes who subverted the mind? Did the Dark Angels help purge Legionaires' memories of the conflict?

[@Armageddon2077]

You have to ask yourself... ... what's worse than turning traitor?

[@samfirth1592]

Or maybe the Dark Angels learned some of their mind affecting abilities by studying the Rangda? Did Russ fight the Rangda, or was it the 6th pre-Russ? If the Rangda relied on psychic powers to control minds and turn brothers against one another then maybe that is why he had such an intense hatred of psykers?

[@CptPanda29]

@@samfirth1592 Russ was the second Primarch found so it's unlikely.

[@ChimpFromSpace]

@@Armageddon2077 Cowardice...

[@Armageddon2077]

@@ChimpFromSpace That and offering aid and comfort to the enemy. Like if they helped Xenos or something?

[@badcarlos551]

Great video. I also like the idea that one of the lost legions/primarchs was, in some way, ideologically opposed to the GC as well as potentially having different 'methodologies' for pursuing it. Purged for not being xenocidal enough seems like a very grimdark explanation

[@MiniPaintAdventurer]

I have a head canon that the second primarch along with the majority of her legion sacrificed themselves in the Horrific battle of the Great crusade to protect the Emperor. A loss so painful to the Emperor that he forbid even the mention of them again to hide the shame of HIS loss.

[@conor4178]

I always wondered if one of them did potentially the most un-40k (or 30k) thing possible. Quit. Got tired of killing during the great crusade, realized what the Imperium was, and just went up to his dad and quit. The big E would probably be livid that his custom built super soldier chose pacifism.

[@adamjohnston4726]

I like the idea that at least one of the two lost Primarchs discovered something/gained knowledge that put the Emperor’s grand plan in danger. We know through Malcador that the Emperor planned for some of the Primarchs to turn against the Imperium but what if one learned of this plan and the Great War against Chaos. Maybe they learned of a different path for humanity that ran in opposition to the Emperor’s more extreme views? What if one of the forgotten Primarchs was the real threat to the Imperium and Horus was just a necessary evil? That would be someone you’d want rid of with no memory remaining.

[@Omni-Man]

I personally think the two Legions were sent to deal with the Rangdan, and either one of them didn't want to commit Genocide or one of the Legions (presumably the Purged) may have fought FOR the Rangdan - seems like something that would threaten the 'ideals behind the Great Crusade'. Imagine if regular Human's heard about an entire Legion rising up for some Xenos.

[@nicholasw777]

The emperor had the ability to obscure peoples memories too, as he did with the Khan, Horus and the Lion. I wonder if whatever happened was one of those situations, where the emperor wiped people's minds. I think you have really good theories on what might've happened though. Makes me think about what if it was kinda like Fulgrim, except with a xenos influence? The opportunity for genestealer-like-cults within a legion would certainly warrant cleansing. Would also make a really cool army :)

[@marktwain7339]

Love the theory that the "idea" of the rangdan could be dangerous. Would add sense to the mindwipe of the primarchs, very eldritch horror i dig it.

[@maxedgecombe8734]

I've only just started getting into Warhammer over the past couple of months, and these videos have been brilliant! I look forward to every new video!

[@apothyon2000]

I've been doing a lot of thinking and a lot of writing around these two legions and my personal interpretation of what could have happened to them. This video is an amazing resource, thank you.

[@dmeep]

when GW finally cave and present what happened it will be a disappointment. Let lost legions be lost. Having the space sharks probably be raven guards instead of their "void father" possibly being one of the lost primarchs was a bad call and i dont see the reveal of one of possibly both lost primarchs going any better.

[@banhammer7243]

I doubt they ever will and quite frankly there is no need to, ever.

[@nekrataali]

@@banhammer7243 There's a bunch of HH secondaries who want more novels and KZbin videos to watch that absolutely want to see every detail about the lost legions. If GW sees that demographic as a bigger money source than the hobby faction, they'll totally pull that trigger.

[@Mickekzon]

@@nekrataali IIRC GW not long ago asked writers to tone down the Lost Legion references and easter egg baits because they want to keep it as mythical as possible.

[@Shane_The_Confessor]

This was very comprehensive and well done. I don't understand the impulse everyone has when they say that we should never know. There is good storytelling potential with these two, and if it's handled well could make for some really excellent reading.

[@Hartmansgrad]

I've always held that because the lost legions were re-distrubuted to the Ultramarines and Imperial Fists, it might be possible to extrapolate details from them by looking at their successor chapters in the 2nd founding. I wonder if one of the lost primarchs was a blank

[@emzetkin1100]

I think a Word Bearer or World Eater said something directly to suggest that, something about the ranks of the Ultramarines growing after Rangda

[@Hartmansgrad]

@@emzetkin1100 My point is this...were the lost legionaries incorporated into the IF and Ultras blended into existing structures or wholesale as chapters within the legions? If they survived the heresy, what happened to these chapters during the second founding? Looking at Ultramarine and Imperial Fist successors, are there any that have peculiar behaviours or mutations not consistent with their supposed primogenitor?

[@doomguy9049]

@@Hartmansgrad like the Soul Drinkers or Mortifactors, for example?

[@alexkaaret]

IIRC, there is a line where Rogal Dorn tells off Sigismund that everyone in my area has interpreted as meaning he (and presumably the Temple Brethren/Black Templars) is from one of the lost legions.

[@ArbitorIan]

The Imperial Fists are most likely for this, since they were known for having quite different cultures between their companies. But then, if Malcadoe mind wiped them, maybe they're just the MOST boring of their Legions??

[@Nertanator117]

Your videos on the lore of the Horus heresy has led me to read multiple novels from the black library. Thank you so much for making quality content.

[@Chruff]

I really like your idea with the Rangda I also think one of the biggest missed opportunities of the Heresy is that Black Library didn’t double down on Russ as the Emperor’s executioner. I love the idea of him being known as having executed the 2nd and 11th (for whatever reason) and the knowledge that Russ is the knife at the back of the other Primarchs makes him a shunned and mistrusted figure. Maybe he doesn’t like his role and privately hates the Emperor for putting it on him but he’s too proud to show the envy he has for his brothers’ fraternity In that alternate reality it should be a big deal if Word is received that Russ is coming to your homeworld and, far from almost being laughed at when the Wolves arrive on Macragge to watch Guilliman, there should be a real sense of threat there

[@graefx]

I like the idea of the records being purged of the first time a primarch is killed. Especially with the death being due to a xenos and no something of the Emperors own making like the traitors. So early all the idea that the emperor and his creations weren't perfect and unbeatable could have destroyed the imperium before it started. It might not be the most compelling reason but it would make the most sense. Then on the other side, a mind virus that literally has power based on knowing about it is the perfect level of scifi existential dread though it kinda clashes with Chaos to me. Ultimately I really like the lost legions just being lost. No explanation, no records, just hushed rumors and half remembered guesses. I like things being unexplained because any explanation will never satisfy everyone more than their imagination

[@mailthedragon]

The lost Primarchs themselves might even be responsible for their records being erased and then disappeared beyond the galactic rim. At one point in the 90's it was suggested that Sigmar was one of the lost primarchs and the warhammer world being somewhere in the 40k universe. This was abandoned. Still it would be awesome to have Stormcast eternals converted to marines and return to the 40k universe as a lost legion.

[@makenamaehara2815]

I still respect the fact that you kept saying HER in the other one. Cracked me up and I loved it.

[@AussieBakester]

Great video Ian, long time viewer from Australia here. Just a quick heads up, Rome lost more than 2 legions at Teutoberg Forest. The 17th, 18th and 19th Legions were lost under the command of Varus. The 9th Legion also disappeared while stationed in Britain. As a History Teacher I had to let you know lol. Keep up the great videos, I look forward to your Tale of 4 Gamers Horus Heresy Edition 😁

[@poppyappletree1400]

I really enjoyed this dive into what's known about these two, and had fun pausing and reading the passages. Thanks for making these videos, I've rewatched the others a bunch, they're just so enjoyable to listen to.

[@samhayden60]

I like the idea that Trazyn has at least one of them and the imperium didn't want to admit any kind of defeat so just removed all record of them, very 1984.

[@theswordsman7590]

I like to imagine that one of the lost Primarchs and their legion were blanks/pariahs and the reason all records of them were scrubbed was due to the fact the Emperor wanted this legion to fight the forces of chaos in secret due to the fact to fight chaos you would be acknowledging the forces of chaos which would power the chaos gods so no knowledge of the warp or those fighting it means no direct actions that would power the chaos gods. If the webway project was successful then humans wouldn’t need to relay on warp to travel and there would be a legion of blanks ready to fight the horrors that may leak from the warp. Thank you for reading and sorry if what I said sounded like utter nonsense.

[@luketfer]

Essentially a Space Marine version of the Psi-Titans. Rarely every talked about, only ever deployed in the upmost dire situations where exterminatus isn't an option and nobody knows where and whence they came but they arrive, fuck everything up with their miniature black hole cannons, then disappear off again with their use only sanctioned directly by the High Lords in modern 40k, even bypassing the Adeptus Mechanicus.

[@watchm4ker]

That role was taken by the Sisters of Silence.

[@hockeymasktime6748]

You always have to ponder what the lost primarchs did considering the actions committed on the regular by angron and the world eaters and Conrad curz and night lords During the great crusade again on the regular

[@TKUltra971]

I love and respect all the time and effort you put into your videos A.I. Most fans go nuts during these discussions asking for proof every 5 seconds with something they don't agree with. But here, its laid out in such a clear cut and to the point format that theres not much of that to be had. Good stuff.

[@adamduncombe594]

Great video. Really well explained and interesting. Thanks for taking the time to share and produce.

[@PrimetimeD]

Excellent deep dive! I've been thinking about these two legions lately, and tying them back to the Rangdan situation would make a lot of sense.

[@instrukt2130]

I had the Idea the Eperor might has seen the shadow of the Warp by the Tyranids from a far as the powerfull Psyker that he is. And as a response he has send a entire Legion to investigate and battle the tyranids in the Void.

[@jumpninja001]

This is I think the most in-depth and well thought out video I' e seen on this subject, and I learnt some new stuff. Well done!

[@psychshift]

You've got such good in-depth lore content, you deserve more subscribers.

[@paladinpariah325]

Your most fascinating and well constructed video to date. Very impressive levels of analysis that take a lot of hard to find disparate threads and weave a captivating narrative.

[@AliAbbasi87]

Ian, I've been obsessed with reading 40k books for around 3 years now and I've read maybe 100 books so far if not more. Been thinking about starting a channel about them and 40k lore and I think your excellent consistency and quality will be the final inspiration needed to push this over the line. Many thanks.

[@Perkustin]

This is now the definitive KZbin video on this subject. Glad your channel is growing ArbitorIan, these Lore AND Hobby retrospective videos are so much better than those 3 hour low effort google image search slideshows. I think even the idea of a Legion being critically damaged early in the Crusade might be too huge a PR disaster to take, there are plenty of advanced human civilisations that came into the fold so maybe if they knew the Legions weren't unbeatable they wouldn't have have signed up. So the simple boring explanation is probably the best. Also iirc in the first Black Book it is mentioned that the Storm Warriors were purged by the War Hounds, i don't think it was just because of a betrayal (or a test of Astartes power) but because the Storm Warriors were living embodiments of how low humanity had fallen. Also maybe at least one of the Primarchs was just utterly incompetent and the Emperor had to make a heart-breaking choice of treating him like any other negligent commander which presumably, given the setting, meant capital punishment. Perhaps the Emperor didn't want a vulnerable moment remembered, or more grimly; he didn't want his reluctance to take the sanction remembered, to keep his other sons in line.

[@Arctik39]

I’ve been waiting for this video ever since you started the legion series! :D

[@Nortonius_]

Love your work. Bringing lit analysis to 40K lore is such a fun and informative perspective on the game and the fiction around it. 👍🏾

[@TheMrFishnDucks]

Awesome video. Well made. Really like that they don't answer this question. Keep up the good work.

[@jackevanson9509]

Great video Ian, I’ve been leaning into this theory for a while ever since BL started giving us lore at how power the Rangda were - I also believe it would have been the DA who purged them! In the lion novel the lion says that his legion are the “sanction” and they would do the acts the space wolves honour would allow them too

[@brianpj5860]

Maybe the Rangdan wars were so bad that a lost Primarch had to disregard imperial sanctions on outlawed technology, and the war was finally won thanks to some super-weapon from the Dark-ages. With the success from whichh having the potential change the way the crusade was operated, leading to an internal fued with Mars. If the Imperium and Mars had a falling-out, that could definitely destroy the great crusade…..

[@dragonsgreedgaming3500]

Loving your vids man. Great stuff and well done!

[@WISHARTfilms]

Incredible work. I love all of your lore videos but this one stands above the rest.

[@miguelolvina1252]

Arbitor Ian back at it again! Lovin the consistent upload sched of quality vids

[@ScampiTheSighted]

FINALLY! All of the information about them, together in one place, and with no dumb speculation! Can't thank you enough.

[@whatapcrk]

Ian, this series of videos is a real highlight of my week. I follow a bunch of lore based KZbinrs but you cut to the chase and don’t fart around without leaving me feel short changed. Your passion shines through and makes it compelling to listen to. I’ve recently returned to the actual hobby proper after a near 25 year absence (I still enjoyed video games and black library books but wasn’t actively painting and modelling) and channels like yours are responsible for me returning to it proper. Thanks mate.

[@ArbitorIan]

Thanks! Although I'm not sure your wallet will be thanking me!

[@whatapcrk]

@@ArbitorIan tell me about it, even that imperium magazine thing is clearing me out let alone my hunger for the heresy boxed set🤣🤣🤣

[@2ndhendrix631]

Damn you're good! Just found you recently and heck your my new favorite! Great narration, no nonsense! Good for someone that just wants the info about the lore without the fuss. Big SUB

[@axelNodvon2047]

Love all the bits from the books that you put in here to see the whole picture

[@angryzergling7832]

Just discovered your content. Your videos are really good and I'm looking forward to watching more of your lore videos! =)

[@KabinMiniatures]

I love this mystery, and I hope it will never be fully revealed. Just like you I will always look for new hints with every novel I read, it's so much fun!

[@Havok448]

So good, great video!

[@peterixon8708]

Love the analysis, love the insight, can even accept the Rangdon hypothesis on the basis of what you presented; well done.

[@MasterShake9000]

Something I think people keep overlooking or failing to understand is that the Crusade Imperium and post-Heresy Imperium are two separate things. The fact that the 2nd and 11th were redacted while the 9 traitor legions weren’t doesn’t really require what the 2/11 did to be “worse” than heresy. It simply means whatever they did happened in an imperium that wanted and was able to suppress knowledge of them. Keep in mind, while the post-Heresy Imperium is a fascist state open to thought control, its religious nature requires the traitors as the “other” that justifies all abuse and violence. It’d go against post-heresy imperial needs to suppress knowledge of the traitors, just as the crusade Imperium’s obsession with unity would want to suppress any knowledge of rebellion (or heighten the natural intimidation base humans experience towards the Marines with knowledge the Marines are capable of turning on them).

[@lv100Alice]

you know. i'm not much of a lore person but i'm pretty sure submite or die is very fashiests as well. that's how the pre herasy imperium did great crusade.

[@MasterShake9000]

@@lv100Alice what is your point? Nothing you said is relevant to my comment.

[@Kepora1]

"The Imperium is Fascist" The administratum WISHES it had that much ability to micromanage, lmao.

[@PeteCrutchfield]

I would love a video on Cypher being Omegon or Alpharius. Excellent video as always

[@noxidninja5109]

I love these videos, always eagerly wait for them

[@FoxHound-ut1hu]

Here's some recent editions to the lore which may prove interesting on the topic of the Lost Primarchs [Dawn of Fire: Wolftime]: " ‘There is division among the Space Wolves regarding the Primaris reinforcements,’ he told the tribune. ‘However, I think the harder Guilliman pushes Grimnar, the more the Great Wolf will resist. The Chief Librarian, Njal Stormcaller, seemed quite amenable and I have established a relationship with him. He may be able to exert more pressure on Grimnar.’ ‘No, you are mistaken. If Logan Grimnar feels betrayed from his own ranks he will react very poorly. Guilliman is waiting for any provocation that would allow him to respond more forcefully, but we should ensure he is not presented with any.’ ‘Speculation!’ said Vychellan. ‘If Guilliman was to turn on the Emperor then the Space Wolves would be one of his first opponents. The history of the Ten Thousand with the Eleventh Legion is a reminder of that. Why would Guilliman be so keen to arm and expand such an obstacle to his ambition?’ " [Alpharius: Head of the Hydra]: "I said nothing. Russ had not listed himself in his speech. There was little doubt what his role was, at least to anyone who had seen the Wolves fight. Russ has a fury in battle that is a near match for Angron’s, but he possesses a tighter focus. The Wolf King is our father’s executioner. I suspect at least one of my departed brothers could have attested to that fact, although I have absolutely no evidence to suggest that is the case. Call it a feeling, if you will." And if we reconcile Russ's statement in Wolf King with what we know from Dorn and Malcador's conversation, it's quite possible that Russ also had his memory wiped of the specifics of the Lost Primarchs.

[@bopman500]

Thanks for putting in the effort to bring this video together, it's really interesting stuff! One character that's always interested me is the first chapter master of the Red Talons, Autek Mor, who's temperament didn't quite suit the Xth legion somehow and some thought that he wasn't from Ferrus Manus' gene lineage. I've always thought he must be a remnant warlord from a lost legion, because it wouldn't really make sense for him to be from an existing primarch's heritage and not be among that respective legion.

[@kylemeyer2139]

Really enjoyed this thanks

[@owmycheek]

Jesus great work Ian! Really comprehensive and interesting!

[@gavinnorton4921]

Excellent, thank you for posting.

[@JK-pp9uz]

loving the lore vids

[@spider8]

I have a theory! Many people have said that if the emperor died, he'd turn into a chaos god, possibly of order. But all of the gods have an opposite, so shouldnt he have one as well? Que malice, remember him? Chaos god of anarchy... and his holy number is 11.

[@asmith9554]

"Que" malice 🤣🤣

[@andrewjamieson7178]

Excellent video!

[@mikenolan73]

There was an episode (137) of the Cast Dice podcast where Rick Priestley talks about the "unexplained" corners of the 40k setting and made a direct comparison between the "lost" legions and the Roman legions in the Teutoborg forest. He hinted that the legions didn't necessarily turn renegade or traitor but that something so awful happened to them the Imperium refused to ever acknowledge what it was.

[@randombencounter263]

I really want at least one of the lost primarchs to have been just a decent and principled human being who opposed the very idea of the Imperium. Maybe they were even raised in a stable and functional mixed human-alien society like the Interrex and refused to be part in blanket genocide of non-humans.

[@Lord_Nielsen]

You’re conclusion is pretty full proof tbh nice job

[@eldraque4556]

nice one Ian!

[@hairydadder1168]

This is definitely the greatest explanation of the two Lost Legions, I love the idea of them being wiped from existence because of some horrific threat even the freaking Primarchs struggled!! Maybe GW setting up a future threat? Maybe the Rangda have something to do with the 'nids? (That was a stretch I know)

[@Yacovo]

Thanks for the video.

[@sylntghost007]

Really love your video’s.how did you come up with your pronunciation for Roboute Guilliman ?

[@LordyT34]

Talking about not one, but two lost legions is some Lamanters level Valor Ian ;)

[@CocoHutzpah]

Since I'm dead-set on the Rainbow Warriors, that's my story for them. The majority of the II Legion, the Rainbow Warriors, fought in the Rangda campaign. Their Primarch, having ruled over a world made prosperous through trade with Xenos, begins to become disillusioned with the Imperium as they struggle against the more superior society of the Rangda. After much of the legion is destroyed in battle, the Primarch and his most trusted troops desert the battlefield and disappear into the galaxy. The remaining forces of the Rainbow Warriors are merged into the Ultramarines and all but their name are scrubbed away. Those that disappeared are rumored to mysteriously return in battles when all seems lost, only to disappear when the battle is won (i.e. The Legion of the Damned).

[@AJNair-cr9uj]

I liked the idea of the Valedictors being the 2nd, and 11th being rainbow warriors. Rainbow warriors were aztec themed, aztecs often did ritual killings and ate them afterwards. (2nd & 11th legions were hinted as being inducted into Fists & Ultramarines). Rainbow legion is now considered a successor of ultramarines. Sons of malice is considered to be of ultramarine stock. Sons of malice are monochromatic, whereas rainbow warriors are... rainbows. 11th legion is also the number of malice. Sons of malice partake in ritualistic cannibalism. Horus dropped (Mal...al) when getting choked out by malcador. Could be trying to say malcador... but the author doing an intentional drop of malal is interesting.

[@UndeadKing_5150]

There's a line in prospero burns where mortarion warns magnus about what he's doing at the council of nikea where this has happened before in regards to the missing legions

[@designjobber]

Right, that's it... I'm signing up to your Patreon. Great video!

[@joenewkirk6136]

Terrific video

[@professorkhepri]

Love your vibeos

[@Hatypus]

Something I would consider is that the lost legions were did not necessarily do something worse than Horus, but that it could have been something easier to cover up and redact than half the remaining legions turning traitor and crippling the emperor and hobling the Imperium, later sparking off the long war.

[@adampoultney8737]

I think they need to explore the lost legions. Once the siege of terra is wrapped up in novel form, the earlier great crusade would be fantastic to see fleshed out. I'd love to see more of some of the primarchs before they fell to chaos (or were enlightened, depending who you ask), or perhaps pre primarch reunification legions. There are over 200 years of Great Crusade history that hasn't been explored in that much depth before the Horus Heresy novel series begins. I don't want just to see the II and XI legions revealed for the sake of filling in that gap in 30k lore, I think it's necessary to do justice to the Great Crusade; or at least the first 150 or so years of it while they were still around. To try to cover it while awkwardly avoiding direct mention by name of the lost legions would be a mistake. The writers from Black Library have done a great job of doing justice to the Horus Heresy, I'm sure they can do justice to the lost legions too. Just imagine the twist if book 1 is a hypothetical Great Crusade novel series went a good few chapters without making it clear what legion the Astartes characters you are following are, dropping occasional hints until a sudden reveal that the characters are actually from the [ REDACTED ]. Perhaps the new hint regarding Subject XI could indicate that Black Library's writers have given the subject more thought. I hope so. They don't even need to necessarily explore their fate immediately

[@TonyEmeryPG20mm]

The brain parasite theory puts me in the mind of "The Hive" from Dark Skies, whole legions lost to such a creature but maintaing their skills and knowledge would be a cool setting!

[@Tulkash01]

I applaud to this video. Well done

[@garayworkshop74]

Someday I will understand why did you leave Alpharius words about the Wolves out of this video... "I said nothing. Russ had not listed himself in his speech. There was little doubt what his role was, at least to anyone who had seen the Wolves fight. Russ has a fury in battle that is a near match for Angron’s, but he possesses a tighter focus. The Wolf King is our father’s executioner. I suspect at least one of my departed brothers could have attested to that fact, although I have absolutely no evidence to suggest that is the case. Call it a feeling, if you will."

[@SuckmyHobnob]

Some things are best left forgotten I guess… Great video!

[@Alstevens83]

Awesome video, I would like to think that before we (as gamers and readers of the Horus Heresy novels) started that one of these legions was sent to do some recon on some far away planet and their Gellerfield's failed and was destroyed in a warp storm. If you think about how dangerous the warp travel was for Garro and co when they were damaged from leaving the Istvan system, So the remaining members of the legion would have gone into say the imperial fists legion. The 11th could have sent two ships to the Rangda system for the war, and this is where the mind-controlling of the 11th primarch comes in. He is mind controlled by the Xeno threat there, and butchers his whole troops near the end of the war, and this is where the Space Wolves come in, they land and look at the carnage on the planet with a broken primarch, not willing to fight to the death, but asking Leman to end his life. The 11th legion Primarch lays his life down for death and this is why Leman later says "I don't think it's possible to kill a primarch" because he hasn't fought one at full strength, he's killed one who has asked for death.

[@JasRGB]

Ooh, this is a great video. One implication of your final theory is that perhaps the mind control extended to the Legions and therefore they fought against each other during the war - the memory wipe then could at least in part have been to spare the Astartes the memory of fighting a large-scale conflict against each other (until of course, the Heresy broke out).

[@diegodankquixote-wry3242]

This is 5 million times better then any of the five billion videos 40k theories has done on the subject or any other youtuber really.

[@caseymay5449]

Good job

[@williamamely7038]

I believe these two Primarchs found out of the existence of the Chaos Gods, and the deal the Emperor made with Chaos leading to the creation of the 20 Sons, and were going to reveal these to their Brothers.

[@thatlonewolfguy2878]

This is my headcanon too, I did a load of digging as well and basically came to the same conclusion, one of them, possibly the 2nd was "possessed" by the Rangda and had to be for lack of a better term, "put down", along with his Legion, the other either fell in battle or suffered from a gene-seed flaw that eventually killed him and his sons too, I like to think the names The Lost and The Forgotten are in order, the 2nd are the Lost and the 11th are the Forgotten, the 11th likely being the ones that fell to a gene-seed mutation so severe that it was worse than the Blood Angels or Space Wolves, that could possibly be where the earliest days of experimentation with chimeric gene-seed came from as the Legionnaires that were folded into the Ultramarines possibly had their gene-seed altered or "corrected" by using existing stable gene-seed to help suppress their mutation possibly