[ITEM]
Dark Heresy Adeptus Astartes Pdf Viewer Rating: 5,0/5 5854 votes

'They shall be my finest warriors, these men who give of themselves to me. Like clay I shall mould them, and in the furnace of war forge them. They will be of iron will and steely muscle. In great armour shall I clad them and with the mightiest guns will they be armed. They will be untouched by plague or disease, no sickness will blight them. They will have tactics, strategies and machines so that no foe can best them in battle.

The Adeptus Arbites is the Imperial Adepta that serves as the galactic police force of the Imperium of Man, responsible for enforcing Imperial Law (the Lex Imperialis) on all Imperial-controlled worlds. They have been granted the right by the High Lords of Terra to serve as judge, jury and executioner to any Imperial citizen they discover having broken Imperial law and the concept of due. The Adeptus Astartes are genetically engineered warriors, created by the Emperor of Mankind and tempered by centuries of bloody warfare. The Index Astartes series explores in detail the many elements of the Space Marines armies on and off the battlefield, from the newly inducted Scouts to the vast battle-barges that carry them to war.

They are my bulwark against the Terror. They are the Defenders of Humanity.

They are my Space Marines and they shall know no fear.' – The on the creation of the Adeptus AstartesAfter he conquered, the set out on a to re-unite the lost human colonies into a mighty. He soon realized that bog-standard humans wouldn't be enough; some situations called for a small number of devastatingly powerful warriors, a surgical strike force to smash enemy linchpins.

To fill this role, he created his, and from their genes, he created the Legiones Astartes, the twenty Legions, in an event named the First Founding. Contents.The Legions Legion NumberPrimarchHomeworldLegion NameAllegianceIABSOLUTELY LOYAL, AND HAVE TOTALLY NEVER BEEN TRAITORS AT ANY POINT. PLEASE FOLLOW ME DOWN THIS ENTIRELY SAFE AND UNSUSPICIOUS DARK ALLEY SO THAT I MAY EDUCATE YOU ON THE TOTALLY CLEAN AND LOYALIST HISTORY OF THE DARK ANGELS!IIRecords expungedIIIAbsolutely FABULOUS traitorIVSuper grumpy TraitorVSpeedy, laughing LoyalVIWho's a Loyal Boy? Ruff ruff yiffVII,MEGA ULTRA FISTISHLY LoyalVIIISpooky traitor (dead)IXLoyal and fabulously DEEAADD!!!XLoyal (also DEAD)XIRecords expungedXII,RAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGE!!!! (traitor)XIIISUPER DUPER Loyal. DEFINITELY never made another Imperium. No chance.XIVIcky traitorXVDid Nothing Wrong Traitors (though they never asked for it)XVIUBER Traitor (and also UBER dead)XVIIThe first TraitorsXVIIILoyal (and with a slightly weird fire fetish)XIXSneaky beaky loyalXXUnknownIt's complicated; even they might not know at this point, but according to the Imperium at large, Traitor.Organization.

The Legio Astartes, being far larger than current Space Marine Chapters, were organized along drastically different lines. At the head of the Legion was its Commander who oversaw the Legion's headquarters. Prior to reuniting with their Primarch, this position was filled by the Legion Master, the most senior Space Marine in the Legion. Below this were the of the Legion, each of which was commanded by a.

Each in turn was divided into a number of Battalions led by a Lieutenant Commander. Each battalion was then further divided into Companies led by a. The Company, itself divided into a number of Squads, was the basic military division of the Legio Astartes.

Due to the varying sizes of each Legion and the varying nature of supply and attrition, there was no fixed number of how many Chapters, Battalions, Companies, and Squads a Legion would contain. But even then, there was no fixed that a particular Company should be composed of certain units, with each Company specialising naturally as marines and officers became veterans of a certain form of warfare.Number of Legionaries The Legions were massive armies, and the size of each could vary tremendously. A precise number was never truly achieved and maintained. Even during the Great Crusade, some Legions were very numerous, while others were not. The numbers would always vary with new recruits and inevitable battle-losses, and also important was the availability of potential recruits and the of the Primarch and his officers.However the closest thing to a 'standard' legion is what the Emperor started with which was 10 chapters to a legion, 2 battalions to a chapter, five companies to a battalion and 100 marines to a company. Theoretical nominal strength: 10,000.The most numerous Legion of all was the.

The of were of a small number as many of them had developed mutations or uncontrollable levels of psychic powers. 's samples had been largely lost, and this left the Legion of the also with a very small number. Both of these Legions would increase their numbers to acceptable standards only after their Primarchs were found.

The, being the first Legion, were originally the largest one but their numbers declined significantly during the Rangdan Xenocides. Main article:For all their power, the and were not perfect; half of them were sufficiently flawed to be tempted by (or driven to), led by Warmaster. The traitors were defeated, but at a terrible cost, including the near-death of the and trillions of deaths of invaluable astartes and human beans.decided that the so-called was proof that one man could not be trusted with power over one-twentieth of the Imperial Armed Forces, so he enacted several reforms to divide the Imperial Army into the Imperial Guard and Navy, and split the remaining loyalist Legions into Chapters, in accordance with his. This event was later known as the.Legions in 40k Technically all of the Chaos Marines are still 'legions', at least in name.

They never split into chapters so legions they technically remain. However, since they are all split up into roving warbands and there is no central control ( ) it's hard to say they really count anymore. Perhaps most importantly it's impossible to guess how many dudes there are even technically in any legions pool. When they aren't fighting the Imperium, they are fighting each other, and since none of the Black Crusades have been successful we can reasonably assume that marines aren't pouring out of the Eye of Terror in their hundreds of thousands.

It's utterly impossible to guess how many dudes they got. They obviously have enough to attack the Imperium with (especially since their recruiting practices aren't as picky as their Loyalist counterparts), but probably not much more than the Loyalist Space Marines. Probably more than they came to the Eye with though, between further recruiting and former Loyalists turning to Chaos.As for the Loyalists.

Since the introduction of the, there are obviously no longer any Space Marine legions though that does not stop certain chapters from being described or implied to be at 'Legion Strength'. Though this is often a common error and sometimes even gets used in the fluff, where the term is mistakenly used to describe any significantly oversized chapter, though even then they never compare to the forces from the Great Crusade. Though some make a good attempt at it:. As it turned out, Dorn didn't fully break up his Legion. Every Son of Dorn chapter has a secret plan dubbed 'The Last Wall'- if the main Chapter were to encounter an immediate threat to Terra, it could call its successor chapters to unite them into a full Legion until the threat is dealt with; the prospect of so many chapters working in such close cooperation was something that frightened the and they did not approve.

Nonetheless, this plan not only saved Terra from, but also rescued the Imperial Fists from actual extinction in the process. are obviously over-strength in multiples of 1000 and keep to the spirit of the Great Crusade unlike any other chapter. This force is made up of three primary crusade fleets of unknown size which can end up spread over up to thirty engagements, where the size of a force could be as large as (but not over for obvious reasons) or as small as a, so can be averaged at around chapter strength for each primary fleet. This arrangement is meant to be fluid, and changes all the time as fleets merge and disperse. Respectable figures put their numbers between 2000-6000. The Templars are able to get away with this due to an obscure exception in the Codex allowing chapters to be over-strength during major Crusades in order to easily replace losses, and the Templars are always crusading. This is unofficially tolerated by the High Lords because of fanatical loyalty, constant casualties, consistent results and the fact that the Templars are so spread out.

They may be legion sized 'total' but there not Legion sized at any single location. make no secret of the fact they ignore the Codex Astartes, but even then they are no-where near their original size. In M32 during the Battle of the Fang it is remarked that most of The Aett is actually abandoned.

Furthermore, Logan Grimnar's own Great Company numbers 200 marines prior to the Sanctus Reach campaign and is the largest company on its own (i.e.: not including the chapter assets). Their current number was originally between 1200-3000, but following the Siege of Fenris it is almost certainly much smaller. were actually accused of Legion building and declared heretics even when they were not yet followers of, their number at the time of the Badab War was around 3000, though they never even used that number as a single force and spread themselves throughout their. are most likely one of the closest examples of a true Legion in that each of the successor chapters arrange themselves under one secret command structure (the Inner Circle). Though they each of the and maintain mostly standard chapters of ten companies. The combined numbers of Dark Angel's successors would put them at around 150,000 marines, and this is just a rough estimate, though we don't know if all of the Dark Angel's successors actually consider themselves part of the Unforgiven.

Some definitely do though. Oh yes indeed. The Inner Circle has been known to send a random successor chapter across the galaxy to do the space marine equivalent of getting them a six pack (of traitors) when the main chapter is too busy. The 23 chapters of the Ultramarines are all represented in the senate of and some of them would cooperate on matters of Codex orthodoxy to ensure that there were no deviations. The in particular routinely loaned squads and officers to the Ultramarines to fill in gaps, while other successors could loan squads to the and get to wear the blue uniform. Because the Ultramarines account for nearly half of the later-founded chapters in the Imperium, they would amount to around 500,000 marines and nominally look to their progenitor for the source of their leadership and guidance, with instances of Marneus Calgar stepping in to settle disputes between chapters not even of his bloodline or issuing decrees against in matters that have nothing to do with the Ultramarines directly. With the return of and his re-organisation of both the Codex and the region of Ultramar; even though chapters officially maintain their sovereignty apart from each other, he has formally created a cross-Chapter command structure of Tetrarchs to coordinate and protect the Five-Hundred Worlds.All of the original legions maintain ties with with their subsequent founding chapters (except for the Salamanders, who don't have any confirmed successors, and ignore the unconfirmed ones), though the level of formality is different from Chapter to Chapter.

The Blood Angels occasionally call all their bros together and go to war, even going to far as to demand they provide the Blood Angels with new squads so that they could rebuild their weakened chapter. The Imperial Fists successors did the same thing during the war of the Beast; donning Imperial Fist colours to ensure that the Chapter would not go extinct.

Viewer

But even in those cases, had to remind that he had no authority to actually demand troops from his successors and might get further by asking nicely. The new Imperial Fists considered changing their colours controversial and a little bit blasphemous, with the generally protesting about Space Marines working in such close cooperation at all. While musing with Aeonid Thiel, Guilliman's original dream for the Codex was not to simply split up the Legions at all, but to create a single unified Legion formed of self-sufficient chapters that would come together or break apart as necessary, irrespective of their individual bloodlines, while making it harder for a taint in one chapter to effect the whole. Given the number of times multiple chapters from different legions have gotten together for a big crusade, he arguable succeed in this goal. Much of what goes on with the Ultramarines tended to done out of starry-eyed respect and deference towards them rather than grudging support, so in this case, their high level of cooperation appears to be following the spirit of Guilliman's original idea quite well.

Obviously, the High Lords would prefer to think otherwise because they were scared to death of the possibility of a second Space Marine unification and uprising, even going so far as to plotting to overthrow the resurrected Lord Guilliman before he took control over the Senatorum (which instantly backfired when the Custodians got whiff of it in about ten minutes, also you know, PRIMARCH).Two Unknown Legions In the of, the twenty First Founding Chapters were all known. It seems that had more love for some than others; when they made revisions in the transition to Second Edition, the and were demoted to one of the 'Later Foundings.' Nowadays, nothing concrete is known about the Legions II and XI, and likewise their.

Officially, the Imperium deleted all records regarding the 'Lost Legions'; the only reminder of the two legions were empty plinths in the Hegemon where statues of the Primarchs stood at the Imperial Palace. Throughout the series, it is suggested that the destroyed them for some reason. Vba query coding in ms excel for mac.

Includes a timeline of the events at the end of the, and in 965 and 969.M30, the Space Wolves engaged in two missions from which all data was redacted. In the book The First Heretic, when a daemon takes the on a trip back in time to show them the creation of the Primarchs, the Word Bearers dialogue indicates that the XI Legion in particular did something bad enough for the Emperor to lead their purge himself.In the book Fear To Tread, Sanguinius tells Horus that he hasn't revealed the existence of the Red Thirst to the Emperor because he fears that the Blood Angels would be purged as well, indicating that gene-seed flaws may have also been a factor. Deliverance Lost has a dialogue between taking place during Corax's first meeting with the Emperor where he asks why only sixteen of his brothers were waiting to meet him if he was the nineteenth Primarch to be found, only for the Emperor to deflect the question; consequently, we can assume that the Legions were purged sometime before Corax's discovery (and were never around for the Horus Heresy). He also forced the remaining Primarchs to swear an oath never to speak of their absent brothers, so whatever they did must have been extraordinarily bad.In Legion, a ship's captain notes that the naughtiness of the isn't the first time that a Legion has 'overstepped it's mark' and that the Imperial Army fleet should report the Alpha Legion 'before they become too powerful,' which might imply that one of the Legions got away with naughtiness for a long time and then used their entire Legion to fight the Emperor. 'Horus Heresy Book 3: Extermination also hints at the fate of the two missing Legions, first hinting that one Legion did not pass the 'Alpha' intake (to take them up to Legion-Strength) when going through testing and the other saying that 'the disaster of REDACTED had proven the folly of attempting to recruit Legiones Astartes stock from potentially tainted sources.'

[/ITEM]
[/MAIN]
Dark Heresy Adeptus Astartes Pdf Viewer Rating: 5,0/5 5854 votes

'They shall be my finest warriors, these men who give of themselves to me. Like clay I shall mould them, and in the furnace of war forge them. They will be of iron will and steely muscle. In great armour shall I clad them and with the mightiest guns will they be armed. They will be untouched by plague or disease, no sickness will blight them. They will have tactics, strategies and machines so that no foe can best them in battle.

The Adeptus Arbites is the Imperial Adepta that serves as the galactic police force of the Imperium of Man, responsible for enforcing Imperial Law (the Lex Imperialis) on all Imperial-controlled worlds. They have been granted the right by the High Lords of Terra to serve as judge, jury and executioner to any Imperial citizen they discover having broken Imperial law and the concept of due. The Adeptus Astartes are genetically engineered warriors, created by the Emperor of Mankind and tempered by centuries of bloody warfare. The Index Astartes series explores in detail the many elements of the Space Marines armies on and off the battlefield, from the newly inducted Scouts to the vast battle-barges that carry them to war.

They are my bulwark against the Terror. They are the Defenders of Humanity.

They are my Space Marines and they shall know no fear.' – The on the creation of the Adeptus AstartesAfter he conquered, the set out on a to re-unite the lost human colonies into a mighty. He soon realized that bog-standard humans wouldn't be enough; some situations called for a small number of devastatingly powerful warriors, a surgical strike force to smash enemy linchpins.

To fill this role, he created his, and from their genes, he created the Legiones Astartes, the twenty Legions, in an event named the First Founding. Contents.The Legions Legion NumberPrimarchHomeworldLegion NameAllegianceIABSOLUTELY LOYAL, AND HAVE TOTALLY NEVER BEEN TRAITORS AT ANY POINT. PLEASE FOLLOW ME DOWN THIS ENTIRELY SAFE AND UNSUSPICIOUS DARK ALLEY SO THAT I MAY EDUCATE YOU ON THE TOTALLY CLEAN AND LOYALIST HISTORY OF THE DARK ANGELS!IIRecords expungedIIIAbsolutely FABULOUS traitorIVSuper grumpy TraitorVSpeedy, laughing LoyalVIWho's a Loyal Boy? Ruff ruff yiffVII,MEGA ULTRA FISTISHLY LoyalVIIISpooky traitor (dead)IXLoyal and fabulously DEEAADD!!!XLoyal (also DEAD)XIRecords expungedXII,RAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGE!!!! (traitor)XIIISUPER DUPER Loyal. DEFINITELY never made another Imperium. No chance.XIVIcky traitorXVDid Nothing Wrong Traitors (though they never asked for it)XVIUBER Traitor (and also UBER dead)XVIIThe first TraitorsXVIIILoyal (and with a slightly weird fire fetish)XIXSneaky beaky loyalXXUnknownIt's complicated; even they might not know at this point, but according to the Imperium at large, Traitor.Organization.

The Legio Astartes, being far larger than current Space Marine Chapters, were organized along drastically different lines. At the head of the Legion was its Commander who oversaw the Legion's headquarters. Prior to reuniting with their Primarch, this position was filled by the Legion Master, the most senior Space Marine in the Legion. Below this were the of the Legion, each of which was commanded by a.

Each in turn was divided into a number of Battalions led by a Lieutenant Commander. Each battalion was then further divided into Companies led by a. The Company, itself divided into a number of Squads, was the basic military division of the Legio Astartes.

Due to the varying sizes of each Legion and the varying nature of supply and attrition, there was no fixed number of how many Chapters, Battalions, Companies, and Squads a Legion would contain. But even then, there was no fixed that a particular Company should be composed of certain units, with each Company specialising naturally as marines and officers became veterans of a certain form of warfare.Number of Legionaries The Legions were massive armies, and the size of each could vary tremendously. A precise number was never truly achieved and maintained. Even during the Great Crusade, some Legions were very numerous, while others were not. The numbers would always vary with new recruits and inevitable battle-losses, and also important was the availability of potential recruits and the of the Primarch and his officers.However the closest thing to a 'standard' legion is what the Emperor started with which was 10 chapters to a legion, 2 battalions to a chapter, five companies to a battalion and 100 marines to a company. Theoretical nominal strength: 10,000.The most numerous Legion of all was the.

The of were of a small number as many of them had developed mutations or uncontrollable levels of psychic powers. 's samples had been largely lost, and this left the Legion of the also with a very small number. Both of these Legions would increase their numbers to acceptable standards only after their Primarchs were found.

The, being the first Legion, were originally the largest one but their numbers declined significantly during the Rangdan Xenocides. Main article:For all their power, the and were not perfect; half of them were sufficiently flawed to be tempted by (or driven to), led by Warmaster. The traitors were defeated, but at a terrible cost, including the near-death of the and trillions of deaths of invaluable astartes and human beans.decided that the so-called was proof that one man could not be trusted with power over one-twentieth of the Imperial Armed Forces, so he enacted several reforms to divide the Imperial Army into the Imperial Guard and Navy, and split the remaining loyalist Legions into Chapters, in accordance with his. This event was later known as the.Legions in 40k Technically all of the Chaos Marines are still 'legions', at least in name.

They never split into chapters so legions they technically remain. However, since they are all split up into roving warbands and there is no central control ( ) it's hard to say they really count anymore. Perhaps most importantly it's impossible to guess how many dudes there are even technically in any legions pool. When they aren't fighting the Imperium, they are fighting each other, and since none of the Black Crusades have been successful we can reasonably assume that marines aren't pouring out of the Eye of Terror in their hundreds of thousands.

It's utterly impossible to guess how many dudes they got. They obviously have enough to attack the Imperium with (especially since their recruiting practices aren't as picky as their Loyalist counterparts), but probably not much more than the Loyalist Space Marines. Probably more than they came to the Eye with though, between further recruiting and former Loyalists turning to Chaos.As for the Loyalists.

Since the introduction of the, there are obviously no longer any Space Marine legions though that does not stop certain chapters from being described or implied to be at 'Legion Strength'. Though this is often a common error and sometimes even gets used in the fluff, where the term is mistakenly used to describe any significantly oversized chapter, though even then they never compare to the forces from the Great Crusade. Though some make a good attempt at it:. As it turned out, Dorn didn't fully break up his Legion. Every Son of Dorn chapter has a secret plan dubbed 'The Last Wall'- if the main Chapter were to encounter an immediate threat to Terra, it could call its successor chapters to unite them into a full Legion until the threat is dealt with; the prospect of so many chapters working in such close cooperation was something that frightened the and they did not approve.

Nonetheless, this plan not only saved Terra from, but also rescued the Imperial Fists from actual extinction in the process. are obviously over-strength in multiples of 1000 and keep to the spirit of the Great Crusade unlike any other chapter. This force is made up of three primary crusade fleets of unknown size which can end up spread over up to thirty engagements, where the size of a force could be as large as (but not over for obvious reasons) or as small as a, so can be averaged at around chapter strength for each primary fleet. This arrangement is meant to be fluid, and changes all the time as fleets merge and disperse. Respectable figures put their numbers between 2000-6000. The Templars are able to get away with this due to an obscure exception in the Codex allowing chapters to be over-strength during major Crusades in order to easily replace losses, and the Templars are always crusading. This is unofficially tolerated by the High Lords because of fanatical loyalty, constant casualties, consistent results and the fact that the Templars are so spread out.

They may be legion sized 'total' but there not Legion sized at any single location. make no secret of the fact they ignore the Codex Astartes, but even then they are no-where near their original size. In M32 during the Battle of the Fang it is remarked that most of The Aett is actually abandoned.

Furthermore, Logan Grimnar's own Great Company numbers 200 marines prior to the Sanctus Reach campaign and is the largest company on its own (i.e.: not including the chapter assets). Their current number was originally between 1200-3000, but following the Siege of Fenris it is almost certainly much smaller. were actually accused of Legion building and declared heretics even when they were not yet followers of, their number at the time of the Badab War was around 3000, though they never even used that number as a single force and spread themselves throughout their. are most likely one of the closest examples of a true Legion in that each of the successor chapters arrange themselves under one secret command structure (the Inner Circle). Though they each of the and maintain mostly standard chapters of ten companies. The combined numbers of Dark Angel's successors would put them at around 150,000 marines, and this is just a rough estimate, though we don't know if all of the Dark Angel's successors actually consider themselves part of the Unforgiven.

Some definitely do though. Oh yes indeed. The Inner Circle has been known to send a random successor chapter across the galaxy to do the space marine equivalent of getting them a six pack (of traitors) when the main chapter is too busy. The 23 chapters of the Ultramarines are all represented in the senate of and some of them would cooperate on matters of Codex orthodoxy to ensure that there were no deviations. The in particular routinely loaned squads and officers to the Ultramarines to fill in gaps, while other successors could loan squads to the and get to wear the blue uniform. Because the Ultramarines account for nearly half of the later-founded chapters in the Imperium, they would amount to around 500,000 marines and nominally look to their progenitor for the source of their leadership and guidance, with instances of Marneus Calgar stepping in to settle disputes between chapters not even of his bloodline or issuing decrees against in matters that have nothing to do with the Ultramarines directly. With the return of and his re-organisation of both the Codex and the region of Ultramar; even though chapters officially maintain their sovereignty apart from each other, he has formally created a cross-Chapter command structure of Tetrarchs to coordinate and protect the Five-Hundred Worlds.All of the original legions maintain ties with with their subsequent founding chapters (except for the Salamanders, who don't have any confirmed successors, and ignore the unconfirmed ones), though the level of formality is different from Chapter to Chapter.

The Blood Angels occasionally call all their bros together and go to war, even going to far as to demand they provide the Blood Angels with new squads so that they could rebuild their weakened chapter. The Imperial Fists successors did the same thing during the war of the Beast; donning Imperial Fist colours to ensure that the Chapter would not go extinct.

Viewer

But even in those cases, had to remind that he had no authority to actually demand troops from his successors and might get further by asking nicely. The new Imperial Fists considered changing their colours controversial and a little bit blasphemous, with the generally protesting about Space Marines working in such close cooperation at all. While musing with Aeonid Thiel, Guilliman's original dream for the Codex was not to simply split up the Legions at all, but to create a single unified Legion formed of self-sufficient chapters that would come together or break apart as necessary, irrespective of their individual bloodlines, while making it harder for a taint in one chapter to effect the whole. Given the number of times multiple chapters from different legions have gotten together for a big crusade, he arguable succeed in this goal. Much of what goes on with the Ultramarines tended to done out of starry-eyed respect and deference towards them rather than grudging support, so in this case, their high level of cooperation appears to be following the spirit of Guilliman's original idea quite well.

Obviously, the High Lords would prefer to think otherwise because they were scared to death of the possibility of a second Space Marine unification and uprising, even going so far as to plotting to overthrow the resurrected Lord Guilliman before he took control over the Senatorum (which instantly backfired when the Custodians got whiff of it in about ten minutes, also you know, PRIMARCH).Two Unknown Legions In the of, the twenty First Founding Chapters were all known. It seems that had more love for some than others; when they made revisions in the transition to Second Edition, the and were demoted to one of the 'Later Foundings.' Nowadays, nothing concrete is known about the Legions II and XI, and likewise their.

Officially, the Imperium deleted all records regarding the 'Lost Legions'; the only reminder of the two legions were empty plinths in the Hegemon where statues of the Primarchs stood at the Imperial Palace. Throughout the series, it is suggested that the destroyed them for some reason. Vba query coding in ms excel for mac.

Includes a timeline of the events at the end of the, and in 965 and 969.M30, the Space Wolves engaged in two missions from which all data was redacted. In the book The First Heretic, when a daemon takes the on a trip back in time to show them the creation of the Primarchs, the Word Bearers dialogue indicates that the XI Legion in particular did something bad enough for the Emperor to lead their purge himself.In the book Fear To Tread, Sanguinius tells Horus that he hasn't revealed the existence of the Red Thirst to the Emperor because he fears that the Blood Angels would be purged as well, indicating that gene-seed flaws may have also been a factor. Deliverance Lost has a dialogue between taking place during Corax's first meeting with the Emperor where he asks why only sixteen of his brothers were waiting to meet him if he was the nineteenth Primarch to be found, only for the Emperor to deflect the question; consequently, we can assume that the Legions were purged sometime before Corax's discovery (and were never around for the Horus Heresy). He also forced the remaining Primarchs to swear an oath never to speak of their absent brothers, so whatever they did must have been extraordinarily bad.In Legion, a ship's captain notes that the naughtiness of the isn't the first time that a Legion has 'overstepped it's mark' and that the Imperial Army fleet should report the Alpha Legion 'before they become too powerful,' which might imply that one of the Legions got away with naughtiness for a long time and then used their entire Legion to fight the Emperor. 'Horus Heresy Book 3: Extermination also hints at the fate of the two missing Legions, first hinting that one Legion did not pass the 'Alpha' intake (to take them up to Legion-Strength) when going through testing and the other saying that 'the disaster of REDACTED had proven the folly of attempting to recruit Legiones Astartes stock from potentially tainted sources.'