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Every time I read the fluff about the Horus Heresy, the one thing that always confused me is why so many space marines turned traitor so quickly, especially against the Emperor?

If the Primarchs were loyal to the Emperor, how could t.hey fall so quickly because of Horus? Did Horus have that much influence? I mean, it is the Emperor we are talking about here. I thought everyone loved him.
Just having a large portion of marines just leaving always confused me. It isn't just a few that left, but entire legions leaving and turning to chaos just makes no sense to me.

How could they turn on themselves so quickly as well? I've read stories about legions after turning gunning down any loyalists. Just doesn't make any sense.


Also, are the traitor legions basically going crazy just the side effects of chaos? I mean, Chaos Space Marines are pretty out there if you ask me.
How do you go from being a cool looking space marine to wanting to serve nurgle and just looking nasty

Maybe I'm just looking to deep into this?


I'm still discovering the fluff, so excuse anything that's wrong or simple.

Watch 10 minutes of network news involving politicians....What was that question on turning on each other?

Its not a sudden day one change. Its a series of events that occurs over decades of war.

Fulgrim and Horus Rising both cover this perfectly.

In both those books the soldiers have been fighting with their Primarchs (their fathers) for so long they have an unbreakable bond with them. More so than that of a distant Emperor (grandfather figure) who many had not seen in decades or more and even more have never fought with them.

Chaos simply has to make the Primarchs turn and in many cases the Primarchs will convince their legions to turn without needing the aid of Chaos.

The second they decided to follow their Primarchs, Chaos is welcomed(at the Primarchs request) and warps the traitors to become the crazy warriors of fluff

 Galdos wrote:
Its not a sudden day one change. Its a series of events that occurs over decades of war.

Fulgrim and Horus Rising both cover this perfectly.

In both those books the soldiers have been fighting with their Primarchs (their fathers) for so long they have an unbreakable bond with them. More so than that of a distant Emperor (grandfather figure) who many had not seen in decades or more and even more have never fought with them.

Chaos simply has to make the Primarchs turn and in many cases the Primarchs will convince their legions to turn without needing the aid of Chaos.

The second they decided to follow their Primarchs, Chaos is welcomed(at the Primarchs request) and warps the traitors to become the crazy warriors of fluff

I agree, bute the primarchs, the pinnacle of the genetic engineering kinda turned too quickly IMHO, especcially Horus, Fulgrim was understandable, Also Lorgar to a degree, Angron was against the Emperor from the beginning, some of the other Primarch are somewhat vague or net yet fully explained.

 Jehan-reznor wrote:
I agree, bute the primarchs, the pinnacle of the genetic engineering kinda turned too quickly IMHO, especcially Horus, Fulgrim was understandable, Also Lorgar to a degree, Angron was against the Emperor from the beginning, some of the other Primarch are somewhat vague or net yet fully explained.

Horus turning was somewhat rushed, but they handwave that away with the Chaos influence from his wound and subsequent mind-jaunt thanks to Erebus.

The other Traitor Primarchs (other than Alpharius) were all in various stages of discontentment to begin with, and just needed a catalyst (although not much of one in the case of the Night Lords or World Eaters) to tip them over into outright rebellion. The fact that they were already switching their loyalty from Emperor to Horus due to his status as Warmaster would have helped influence their turning as well.

So, general discontentment with their lot, stoked carefully by the artfully placed Word Bearer Chaplains in their midst, building up to the point where Horus says 'Follow me, lads, let's go burn stuff!'...

lettuceman44 wrote:
I thought everyone loved him.

It is this preconception which is causing your confusion.

Everyone did not love the Emperor. Angron hated him. Konrad Curze thought he was a hypocrite and had dreams of the Emperor killing him. Mortarion was always pretty sinister, and required little coercing to make him turn because he also despised the Emperor. Perturabo was resentful of him. Fulgrim wasn't but there were extenuating circumstances surrounding his betrayal. Lorgar was turned against the Emperor when he destroyed Monarchia. Magnus turned from the Emperor out of desperation. Alpharius turned because he's an idiot.

 Galdos wrote:
Its not a sudden day one change. Its a series of events that occurs over decades of war.

Fulgrim and Horus Rising both cover this perfectly.

I agree with this here. Except the part about Fulgrim being, in any way, a quality piece of work. Just kidding. The salient point here is that it wasn't a sudden shift. While it seemed that way to some of the marines who didn't realize what was going on, (the people who died on Istvaan III and V, f'rex) in reality the culture of secrecy fostered by the warrior lodges had coupled with dissatisfaction from a number of the Emperor's policies or past decisions, and by the time they culminated in full scale revolt, they had been brewing for several decades.

I've been reading Fulgrim recently and their downfall is portrayed quite well. They want to prove themselves and achieve perfection, and the Mehreens are loyal to Fulgrim, first and foremost. Then, they're all influenced by the Slaanesh-tainted world of Laer. Fabius doses them with combat drugs, Fulgrim obtains a Daemon Weapon that constantly influences his mind, then Ferrus Manus angers him by foiling Fulgrim's plan, etc., etc. It doesn't seem like one day they just decided, "Hey lads, let's be evil now!". It was a gradual process which could end in only one way.

And obviously, not entire Legions were swayed to the side of Chaos. Emperor's Children lost nearly half of their manpower at the Drop Site Massacre, for instance.

It's supposed to be a gradual chipping away and an eventual fall to corruption. The problem is they can't necessarily show this in it's entirety in a series of books as they want to keep the reader entertained and reading. So although it might seem like a fairly fast fall in the series, which is one of the gripes I hold, it is supposed to be as mentioned, a fall over a period of time for various reasons and issues that the Primarchs and their Legions harbour.

Marines are indoctrinated to be loyal to their brothers and to their Primarch. Their Primarchs were virtual demigods fighting alongside them. The Emperor became more and more distant a figure, and Terra a distant place that no longer had any emotional meaning.

However the greater issue (and one which the novels do not do well in illustrating) is the struggle for civilian control of the military within the Imperium. The Primarchs are all basically warlords, with vast personal armies and fleets. Part of the discontent stemmed from their unwillingness to submit to the civilian administrative structure of the new Imperium. Their own reasons vary but underlying it all is often a streak of feeling themselves better than normal humanity, and that therefore they should be the ones in charge. We can see the result of this in the societies of the Chaos Space Marines in the Eye of Terror which generally have the CSM as a ruling warrior class with normal humans as downtrodden slaves and expendable cannon fodder.

Thematically the Heresy is a take on the Christian War in Heaven myth with Horus filling the role of Lucifer. Like the War in Heaven, the Heresy can be viewed as a refusal by superior "angelic" beings to submit to a perceived inferior species (humanity in both cases).

Where the novels fail is in dealing with this theme in a nuanced way and the the thing comes off as a bad superhero/supervillain comic.

The mere act of following your Primarch (even unknowingly) in the pursuit of Chaos related goals is enough to let the corruption influence you.

 Pilau Rice wrote:
It's supposed to be a gradual chipping away and an eventual fall to corruption. The problem is they can't necessarily show this in it's entirety in a series of books as they want to keep the reader entertained and reading. So although it might seem like a fairly fast fall in the series, which is one of the gripes I hold, it is supposed to be as mentioned, a fall over a period of time for various reasons and issues that the Primarchs and their Legions harbour.

It took 3 Years for Horus(well more like 30, but the first 27 were failed campaigns/diplomacy and doubting himself; the final 3 were pride/self reliance mixed with Erebus' whispering/conspiracies). Horus' fall made the most sense when readingb the first couple Horus heresy books.

Fulgrim took about 4-5 years and that was with both Pride/ambition as a starting point and then a daemon weapon filling his mind with horrible thoughts. While Fulgrim didn't do much to actually resist Chaos, he took the longest to actually convert(although it seems like a switch got flipped if you do not look at the timeline).

Iracundus wrote:
Marines are indoctrinated to be loyal to their brothers and to their Primarch. Their Primarchs were virtual demigods fighting alongside them. The Emperor became more and more distant a figure, and Terra a distant place that no longer had any emotional meaning.

However the greater issue (and one which the novels do not do well in illustrating) is the struggle for civilian control of the military within the Imperium. The Primarchs are all basically warlords, with vast personal armies and fleets. Part of the discontent stemmed from their unwillingness to submit to the civilian administrative structure of the new Imperium. Their own reasons vary but underlying it all is often a streak of feeling themselves better than normal humanity, and that therefore they should be the ones in charge. We can see the result of this in the societies of the Chaos Space Marines in the Eye of Terror which generally have the CSM as a ruling warrior class with normal humans as downtrodden slaves and expendable cannon fodder.

Thematically the Heresy is a take on the Christian War in Heaven myth with Horus filling the role of Lucifer. Like the War in Heaven, the Heresy can be viewed as a refusal by superior "angelic" beings to submit to a perceived inferior species (humanity in both cases).

Where the novels fail is in dealing with this theme in a nuanced way and the the thing comes off as a bad superhero/supervillain comic.

^Mostly this.

The Heresy was inspired in "real" legends / religions, and it worked fine while it stayed a legend. Then came the novels. Some Horus Heresy novels are good, others are bad, but all of them take the "legend" down to reality. The way they are written, it gives the impression that the Primarchs are teenagers with daddy-issues. But if you take them one by one, most of them had good reasons to fall:

1) Curze was driven insane by visions of his own death at the hands of an assassin sent by his father. This lasted years, and his descent into darkness was progressive.

2) Angron hated his father. With good reasons. He only accepted the position of leader of the XII Legio after Kharn convinced him that the Legion would follow him, and not his father, in the event of a war between father and son. Angron never hid his opinion on his father, and tried to kill him at least once before the Heresy.

3) Mortarion was resentful of his father since he meddled in his fight with his other father. He also saw the Emperor as a tyrant, and was quite vocal in his negative opinions on what was going on in the Imperium. And at the end he was forcibly turned to Chaos.

4) Perturabo never intended to rule. He was happy being the second in command of his foster father, Dammekos. He is the only Primarch that didn´t even try to be a leader. He was forced to do so, and despised for his lack of interest. He tried to compensate it, and failed. Then his foster father died, the planet started an all-out rebellion and he brutally repressed it. And something else happened that he thought would be unforgivable by the Emperor.

5) Lorgar believed that he was doing the right thing and, in most ways, kicked off the Heresy. He is a religious fanatic, and his decision a long-time meditated one. It was a decission based on faith. Do not underestimate the influence of his foster father, Kor Phaeron, in the fall of Lorgar, and do not underestimate the influence of Lorgar, Erebus and the rest in the fall of the other Legions.

6) Magnus was manipulated by forces really good at manipulation. It was a trick that needed decades to work and involved some other Legions, such as the Wolves.

7) Fulgrim was by far the proudest of them all. He saw himself as far superior than anyone, with the universe and everything in it created just for his pleasure. A little push by a Daemon was enough for his fall.

8) Alpharius was an idiot. The reason for his turning was unclear in the old background so we only know what the HH novels says: a total idiot. The OP is right on this one: his betrayal was sudden and without reason. He is the exception.

The hardest one is Horus, because we know how long and convoluted his fall was, yet we don´t know what were the real reasons behind it. We saw what he saw, and know that he made the decision by himself. But we don´t know why. However, we see Horus smashing his fist in rage against the tank of the Primarch of the XI Legion, we know that the Thunder Warriors were killed when they were no longer needed, we know the Emperor was forcing his sons to take orders from the High Lords, puny humans all of them, we know that princes rebelling against their fathers are quite common in history, especially if the father refuses to get old and die...

All Primarchs had good enough reasons to fall. And it took years. Alpharius is the exception.

Because Erebus is really good at his job.

He and Kor Phaeron are the real architects of the Heresy. Erebus out of fanatical devotion to Chaos, Kor Phaeron out of megalomania. Together, they epitomize everything that the Chaos Legions would become.

It is trite though some works have helped flesh out some of the betrayals.

Horus is given 3 (well written) books to explain his fall and Magnus is well explained by his own novel as well.

The problem is that the BL authors are pidgeonholed into forcing characters into a pre-written story. They fell to chaos because they must.

Take Mortarion for example. He is, according the books, like the last primarch that should fallen. He hates weakness and sorcery in all its forms after growing up under the rule of a chaos sorcerer on his home world. For all intents a purposes he could have been an order malleus inquisitor with that backround. Instead, we are forced to find some reason that he fell; in this case some flimsy grudge against the Emperor.

My personal problem with the story is that so much of it could be solved if the Emperor simply sat his genetically engineered supermen down one day, explained chaos and its nature, and to not listen to the bad voices in their head. That screams bad plot structure to me.

So, in sum, they fell so quickly because the overall story demanded that those legions must fall and the reasons seem trite in many cases because the BL authors don't have a lot of room to create real tragedy or passion for why someone would betray their father, their race, and their souls for often juvenile and shallow reasons (I'm looking at you Alpharius).

As to the other question of how come whole legions turned... well they didn't. It was quoted that the traitors purged up to a 1/3 of their numbers at Istvann III who were considered too loyal to be turned. Admittedly that was only 4 of the 9 legions but some of the others were apparently culling their own numbers as well.

The shift was not as sudden as the OP makes it sound. Seeds of doubt were planted and then cultured and grown until they blossomed into out right rebellion.

There is a quote that goes something like this. "The path to damnation is not taken in leaps and bounds but a series of steps. "

The same holds true for most of the legions that went renegade. Many of them took their first steps towards chaos thinking they were taking steps to make a better Imperium.


Also another point I have not seen mentioned is the fact that many Astartes were afraid and more than a little disgruntled. The crusade was nearing its end, and as each planet was brought to compliance it was put under civilian leadership. It is mentioned in several HH books that once the galaxy was conquered that the Astartes feared they wouldn't have a job or more importantly a place in the newly created Imperium. This did not sit well with many legions, especially the ones who had to "double back" to reconquer worlds that had been brought into compliance and then corrupted by the politician they had left in charge.

Not hard to see at all why they began treading down that road.

Oh and anyone that calls the twin primarchs idiots has clearly not read Deliverance Lost. Any legion that can infiltrate every other legion is clearly not an idiot. Insane maybe.. idiot.... NO.

Another reason for the easy fall to renegades, if not chaos: As the crusades were launched, many legions had their ranks swelled VERY rapidly. Space Marines are supposed to undergo years of indoctrination, but the needs of the crusades cut this short. One theory is that these marines, though loyal to their chapter and brothers, weren't necessarily loyal to the Imperium as a whole. Additionally, they were easier to manipulate. I think the HH:Betrayal book form Forge World speculates on this some.

 buddha wrote:


Take Mortarion for example. He is, according the books, like the last primarch that should fallen. He hates weakness and sorcery in all its forms after growing up under the rule of a chaos sorcerer on his home world. For all intents a purposes he could have been an order malleus inquisitor with that backround. Instead, we are forced to find some reason that he fell; in this case some flimsy grudge against the Emperor

Mortarion fell because he's a bad person. The most sinister of the Primarchs.

 Kommissar Kel wrote:

 Pilau Rice wrote:
It's supposed to be a gradual chipping away and an eventual fall to corruption. The problem is they can't necessarily show this in it's entirety in a series of books as they want to keep the reader entertained and reading. So although it might seem like a fairly fast fall in the series, which is one of the gripes I hold, it is supposed to be as mentioned, a fall over a period of time for various reasons and issues that the Primarchs and their Legions harbour.

It took 3 Years for Horus(well more like 30, but the first 27 were failed campaigns/diplomacy and doubting himself; the final 3 were pride/self reliance mixed with Erebus' whispering/conspiracies). Horus' fall made the most sense when readingb the first couple Horus heresy books.

Fulgrim took about 4-5 years and that was with both Pride/ambition as a starting point and then a daemon weapon filling his mind with horrible thoughts. While Fulgrim didn't do much to actually resist Chaos, he took the longest to actually convert(although it seems like a switch got flipped if you do not look at the timeline).

Exactly, the scale of duration is lost in the actual series, as are the shifts from loyal to traitor, we see a glimpse of the rot spread, but not how it necessarily takes over the Legion.

I would disagree with you about the Horus fall, but other than that.

 buddha wrote:


My personal problem with the story is that so much of it could be solved if the Emperor simply sat his genetically engineered supermen down one day, explained chaos and its nature, and to not listen to the bad voices in their head. That screams bad plot structure to me.

But the Emperors final plan is to reach God-Hood by all the Humans worshiping him.

 da001 wrote:

8) Alpharius was an idiot. The reason for his turning was unclear in the old background so we only know what the HH novels says: a total idiot. The OP is right on this one: his betrayal was sudden and without reason. He is the exception.
...
All Primarchs had good enough reasons to fall. And it took years. Alpharius is the exception.

Did no one in this thread read 'Legion'? Alpharius "fell" in the sense of turning traitor quickly. At the same time, there was a reason ("killing" the Chaos gods), and it's not clear if he fell in the sense of turning to Chaos. Other reasons are the sense of inequality between him and his brothers; Guilliman repetitively berated Alpharius's tactics, which drove him to do more impressive feats of tactical genius, which were unconventional, and so Guilliman would chew him out again. Killing a quartet of gods would be quite the feather in Alpharius's cap. Another point is that the only other primarch who showed him a sense of brotherhood WAS Horus. While Sanguinus and Horus were BFFs, Alpharius had no one else at all, which makes his siding more reasonable.
Look at the structure of the Alpha Legion too. It is encouraged for battle brothers to question anyone else before combat, to try and tease out the failings in a plan. Philosophy was a favored pastimes among the AL, and if they didn't once sit down and question the Emperor's choices and actions, then I'll eat my Helbrute model. The AL were also duplicitous beyond words; he shown a prophecy that his brothers would turn against each other and plunge his entire species into a civil war that may end in humanities extinction. Since the AL were/are spies and saboteurs beyond almost any other force, it makes sense that they would play to that strength and "join" Horus. Did they eventually turn fully? I dunno, given how rare AL fluff is (which doesn't help make the AL look anything other then kinda schitzo, flitting between brilliance and window-licking) it's really hard to say anything of substance about them.

I disagree that the Alpha Legion and Alpharius were idiots.

I have read Legion and I believe that, being shown a vision of the future of their species (either quick, fairly merciful destruction or a slow decline towards death) he picked the lesser of two evils that would also end up with the elimination of chaos.

I also don't believe that the Alpha Legion turned to chaos, at least not originally. Who knows what has happened to them after 10,000 years though?

The Alpha Legion are (probably) like terrorists/freedom fighters (same thing); while they don't actually worship Chaos and are loyal to humanity, they see the Imperium for what it is - a big, nasty, brutal mess - and want to tear it all down. It's quite possible that Alpharius has or had a hand in these actions. This is post-Heresy of course, but it does speak of his greater motivations/character if it is indeed his influence and not just the Legion acting without him (although, being the Alpha Legion, they would mostly like act exactly as he would, anyway, what with the whole hydra thing).

Also, as stated before, Alpharius' friend was Horus. If anyone was an idiot, it was the Emperor for allowing his children to develop specific allegiances and so on, and for all the things he did that just served to make them angry (Angron, Mortarion, Lorgar). Examples like not telling Magnus why he couldn't use magic, instead of just ordering him not to and then expecting him to obey (which he did, until circumstances forced his hand). Tearing down Lorgar's golden palace and humiliating him instead of sitting him down and explaining "Now son, this is why we don't worship me as a god" was just being a massive prick.

Also, if Magnus could contact The Emperor psychically, surely The Emperor could have contacted all of the Primarchs with the PSA "Your big brother is evil"?

 rohansoldier wrote:
I disagree that the Alpha Legion and Alpharius were idiots.

I have read Legion and I believe that, being shown a vision of the future of their species (either quick, fairly merciful destruction or a slow decline towards death) he picked the lesser of two evils that would also end up with the elimination of chaos.

I also don't believe that the Alpha Legion turned to chaos, at least not originally. Who knows what has happened to them after 10,000 years though?

"Xenos told me to betray the Emperor so I did" < Best reason ever.

The fluff seems fairly consistent that, for the most part, the Marines were far more loyal to their primarchs than to the Emperor.

When you examine classical groupthink in situations where there is a strong central authority figure, it seems fairly easy to believe that the Legionnaires could turn on their brother Space Marines if they've been told to do so by their Primarch.

"Those guys aren't part of the group. They've betrayed our bonds of brotherhood, and aren't part of our group."

Esprit de corps is extremely important to military organizations, and speaking as a real life Marine, there were few things more distasteful than stories about Marines who violated that bond or made the Marine Corps look bad. And the Space Marines are even more fanatical.


Now, with that understood, you have to look at the Primarchs themselves. Now, first and foremost, it's important to understand that the fluff is rooted in stories told more than twenty years ago when it was okay to be Angron the daemon primarch of the god of being angry, or Mortarion, daemon prince of the god of death and decay and be a giant reaper looking guy replete with scythe. So the primarchs, like the Emperor, suffer pretty heavily (in terms of story believability) from predestination. They were written to do the things they did when they were, as characters, little more than one-dimensional names on paper. So always keep that in mind when you're trying to figure out the "why". Ultimately, the answer is always "because GW said so." The Black Library has to work within those confines. Sometimes it works (Lorgar) and they can create a fairly believable motivation for them, sometimes it doesn't (Angron) and the story just gets dumber the more that is written trying to explain it.

But when you look at the primarchs, the ones who fell, for the most part, have fairly simple archetypal motivations. Most of them revolve around the Seven Deadly Sins. Most commonly Pride, Envy and Wrath, but a little bit of Greed and Lust(lust, in the sense of sin, isn't just sexual in nature, it's more about "desire" in general) mixed in for some.

It came down to Chaos manipulating the weaknesses of the traitor primarchs. Ultimately, they were the vulnerable ones. Certain primarchs wouldn't have fell because their personalities and values didn't include traits the chaos gods could exploit. Russ, for example, was too loyal, too unquestioning. There was nothing for Chaos to offer him that would give him something he felt was missing. Guilliman (and Dorn to a lesser extent) is entirely based on the Roman virtues of Gravitas (Seriousness/Dignity), Pietas (Duty/Loyalty), and Virtus (various masculine traits like valor, courage and character). Again, there was nothing for Chaos to offer him that he didn't already get from simply doing his perceived duty to mankind and the Emperor.

The primarchs who turned had doubts. Or they had needs which the Chaos gods could fill. Now, these are generalizations, and several of the primarchs had multiple motivations, but for example: Lorgar needed validation. Angron needed an outlet (we'll ignore the Grand Canyon sized plot holes in his character and back story, and just accept that Angron is angry). Fulgrim was obsessive. Curze was mentally unbalanced and plagued by visions of treachery. Perturabo felt marginalized. You get the point.

Other, less well defined primarchs fell or didn't fall by virtue of "because we said so". Corax, Vulkan, Khan... they had very tiny roles in the original fluff. They were loyal because there was next-to-nothing written about them, and somebody had to stay loyal. Ferrus died, obviously. And Sanguinius was the martyr. Lionel had his own unique background which has always involved a lot of "mystery".

 Void__Dragon wrote:

 rohansoldier wrote:
I disagree that the Alpha Legion and Alpharius were idiots.

I have read Legion and I believe that, being shown a vision of the future of their species (either quick, fairly merciful destruction or a slow decline towards death) he picked the lesser of two evils that would also end up with the elimination of chaos.

I also don't believe that the Alpha Legion turned to chaos, at least not originally. Who knows what has happened to them after 10,000 years though?

"Xenos told me to betray the Emperor so I did" < Best reason ever.

Come on dude, that's a gross oversimplification of what happened. The Cabal didn't say "Hey, we don't like the Emperor, you should help Horus kill him dead", they said "Dudes, either your race dies in about a hundred years and it's all fairly quick if brutal OR you suffer for ten thousand years (with no hope of recovery from such a crippled state) and THEN die, taking most of the universe with you. So spare your race some suffering and go double-tap the Emperor." AL had plenty of reasons to "betray" the Emperor. Do they all add up to a 'good enough' reason? I dunno, mostly because I dunno if AL ever really fell. But come on, don't just degrade the AL to the level of easily mislead children.

The Alpha Legion fluff is universally awful.


And this coming from a former Alpha Legion player from the old days. Hands down the most irretrievably ruined Legion fluff.

Looks like there were some things I didn't know. Thanks for the information, the Horus heresy doesn't seem as confusing anymore.

Still tough for me to accept so many turning to chaos haha. Like who wants to serve nurgle :p

lettuceman44 wrote:
Looks like there were some things I didn't know. Thanks for the information, the Horus heresy doesn't seem as confusing anymore.

Still tough for me to accept so many turning to chaos haha. Like who wants to serve nurgle :p

A lot of it was destined to happen in away, Nurgle had his claws in Mortarion since his sojourn in the warp and landing him on Barbarus.

Mortarion was forced into service again by Nurgle, like he was the Emperor, Nurgle saved him and forced him to be his newest servant. Mortarion and the Death Guard didn't have much choice in the matter, the only ones who welcomed it were Typhon and his followers.