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Oh definitely.

And with the hint, possibly Party Political Broadcast, that the Primarchs are in part manifestations of the Emperor’s psyche, and so every bit as flawed in their vision and outlook as He is.

Now, is that ingrained in their nature, or part of Golden Child syndrome, having all grown up with zero direct equals and peers, and pretty much always being The Most Special Person In The Room? Is a conversation entirely unto itself. Could be six of one, half dozen of the other.

A.T. wrote:

Eumerin wrote:
"noped out immediately..."?
Russ left a little over two centuries after the Heresy.

Original Russ went straight for the eye of Terror, when and why he went came later.

Original mention of his departure had possible reasons why, one of which was "looking for Johnson, who had disappeared."

I was just wondering when it was first a thing and whether it is portrayed as particularly unique to Fenris

The original Space Wolf codex mentioned the Wulfen Curse, and the unfortunate fate of the Wolf Brothers chapter (the Space Wolves' sole successor chapter) as a reason why people suspected there was something unique to Fenris that kept the Wulfen Curse manageable - as opposed to going totally out of control, which appears to have been what happened to the Wolf Brothers. So there's always been a suggestion that there's something important about the planet itself, though it was always speculation both in-universe and out.

 insaniak wrote:

 Dysartes wrote:
General question, from someone who has avoided most of the HH books - do any of the Primarchs come out looking better after the HH material that's been released compared to how they did before?

Sanguinius largely remains unblemished. The Khan got something of a glow-up. Other than that, the loyalist primarchs were largely portrayed as arrogant and unlikeable, while the renegades were mostly fleshed out into tragic characters let down by the Imperium and the Emperor.

"Sanguinius largely remains unblemished".

That's because he's a pathetic Mary Sue. The absolute worst thing to happen in both 30k and 40k storytelling. Just give him a single flaw ffs. Make him interesting.

 insaniak wrote:

 Dysartes wrote:
General question, from someone who has avoided most of the HH books - do any of the Primarchs come out looking better after the HH material that's been released compared to how they did before?

Sanguinius largely remains unblemished. The Khan got something of a glow-up. Other than that, the loyalist primarchs were largely portrayed as arrogant and unlikeable, while the renegades were mostly fleshed out into tragic characters let down by the Imperium and the Emperor.

Eh... I think they tried to flesh out the traitor Primarchs into tragic falls, but I don't think they pull it off for most of them, at least in the novels. Frankly, most of the traitor Primarchs also come across as arrogant and unlikeable, or their falls are "they were great then this Chaos artefact corrupted them", probably due to Erebus. The whole thing is basically a petty soap opera. Honestly, if Erebus had eaten a bullet in his first battle, the Horus Heresy might not have happened at all, as the novels present it...

I think the FW Horus Heresy books actually do a better job here. The Iron Warriors seem much more sympathetic in those IMO.

 Gadzilla666 wrote:

 insaniak wrote:

 Dysartes wrote:
General question, from someone who has avoided most of the HH books - do any of the Primarchs come out looking better after the HH material that's been released compared to how they did before?

Sanguinius largely remains unblemished. The Khan got something of a glow-up. Other than that, the loyalist primarchs were largely portrayed as arrogant and unlikeable, while the renegades were mostly fleshed out into tragic characters let down by the Imperium and the Emperor.

"Sanguinius largely remains unblemished".

That's because he's a pathetic Mary Sue. The absolute worst thing to happen in both 30k and 40k storytelling. Just give him a single flaw ffs. Make him interesting.

The flaw comes in the Blood Angels themselves though. Having Sanguinius as this perfect vision, and every single one of his golden child genetic progeny over 10,000 years being subject to a horrendous curse is quite powerful to me on its own.

I am very much in the camp that providing so much detail in Primarch Street lessens the mythological aspect of the Primarchs that I found fascinating from the get go, and have therefore deliberately not really engaged with it very much.

They've kind of gone back and forth on the blood angels' flaw thing too. I was under the impression, in the heady days of 2005, that both the flaws in the Blood Angels came as a result of Sanguinius' death and the resultant psychic whatever, but the novels make it so the bloodthirst was there before, but also they control it in a similar way to the rage.

Eventually it becomes established that prior to Sanguinius the ninth was much more ghoulish and that he did a lot to clean up their image, but there's still the chance that it leaks out.

But in all of this HE remains a pretty classical noble hero (insofar as anyone who stands for the Imperium can be, so only in the totalitarian sense) without any major failures. He's sad a bunch but not debilitatingly depressed, for the most part.

Vulkan also comes out kind of squeaky-clean, except that he just keeps run into Worf effect situations where he just suffers a lot.

Re: Fenris being special; planetary spirits aren't THAT weird, especially in the context of 40k where belief does matter. Nocturne's got the same vibe, Caliban has a whole spiritual manifestation thing going on.

I'm not convinced that a Magic Planet Spirit being "real" is any particular vindication of the Space Wolf position at Nikaea, since Rune Priests ARE psykers, and they certainly didn't stop using them.

Dorn and Corax for example did either cloister their psykers or return them to normal ranks.

The thing is, the Rune Priests are psykers. I never said they weren't; the Space Wolves might believe that. They're wrong. They're just doing it in a controlled, disciplined way, same as the Zaydin Arga or Stormseers as they are crudely called. The world-spirit is a tool in the discerning psyker's tool box.

Magnus is seeking to gather everything too quickly. He needed to slow his roll. But instead he was a two-pump chump who couldn't keep his hands to himself.

Regarding planetary spirits- Exodite worlds (and maybe Maiden worlds?) have a world spirit which is used in lieu of an infinity circuit by the Exodites.

It may be the case that all planets have one, but only Eldar can reliably tap into them.

IIRC, realspace gravity affects the Warp, which is why entering or exiting the Warp too close to a star is incredibly dangerous. Therefore there is precedent for inanimate objects having a Warp presence of some form.

 Haighus wrote:
Regarding planetary spirits- Exodite worlds (and maybe Maiden worlds?) have a world spirit which is used in lieu of an infinity circuit by the Exodites.

It may be the case that all planets have one, but only Eldar can reliably tap into them.

Exodite world spirits are used to house the souls of their dead, and keep them from being eaten by Slaanesh. I think it's fairly safe to say that whatever is in Fenris is not the same thing. It's also unlikely that Fenris is a former Exodite world. The Exodites ran long, fast, and early from the impending collapse of their empire. That empire was centered around what is now known as the Eye of Terror, and Fenris is (galactically speaking) not all that far from the Eye. If there were ever any Exodites that set foot on Fenris in the distant past, they only did it as a temporary stop on their way to much, much further locales.

The world spirit of Fenris has apparently been mentioned on occasion in the novels, with indications that it's more than just Wolf Priest superstition. But afaik, the first mention of it within the game is in the campaign involving the recent attack on Fenris. Prior to this, in-game (i.e. ignoring the novels) lore stated that many believed some unknown aspect of Fenris worked to make it possible for a Space Wolf aspirant to keep the Wulfen Curse in check. Without the influence of Fenris, the eventual result would be the same fate that happened to the Wolf Brothers chapter. Note that this dates back to the original Space Wolves codex - i.e. before things like Thunder Wolf cavalry were added to the chapter.

Eumerin wrote:

 Haighus wrote:
Regarding planetary spirits- Exodite worlds (and maybe Maiden worlds?) have a world spirit which is used in lieu of an infinity circuit by the Exodites.

It may be the case that all planets have one, but only Eldar can reliably tap into them.

Exodite world spirits are used to house the souls of their dead, and keep them from being eaten by Slaanesh. I think it's fairly safe to say that whatever is in Fenris is not the same thing. It's also unlikely that Fenris is a former Exodite world. The Exodites ran long, fast, and early from the impending collapse of their empire. That empire was centered around what is now known as the Eye of Terror, and Fenris is (galactically speaking) not all that far from the Eye. If there were ever any Exodites that set foot on Fenris in the distant past, they only did it as a temporary stop on their way to much, much further locales.

The world spirit of Fenris has apparently been mentioned on occasion in the novels, with indications that it's more than just Wolf Priest superstition. But afaik, the first mention of it within the game is in the campaign involving the recent attack on Fenris. Prior to this, in-game (i.e. ignoring the novels) lore stated that many believed some unknown aspect of Fenris worked to make it possible for a Space Wolf aspirant to keep the Wulfen Curse in check. Without the influence of Fenris, the eventual result would be the same fate that happened to the Wolf Brothers chapter. Note that this dates back to the original Space Wolves codex - i.e. before things like Thunder Wolf cavalry were added to the chapter.

Exodites may not have created their world spirits though, they could be something that every planet has which they're using in a specific way. I don't think "this planet has a psychic spirit that we use for a specific psychic purpose" is all that different from Fenris.

 Haighus wrote:

Exodites may not have created their world spirits though, they could be something that every planet has which they're using in a specific way. I don't think "this planet has a psychic spirit that we use for a specific psychic purpose" is all that different from Fenris.

1.) Exodite world spirits are described as having artificial structures built by the Exodites to support their existence on their planet. The world spirit is able to influence the physical world immediately around these areas, to the point where it can animate objects and engage in combat. But it can only directly influence the area immediately around these objects.
2.) Exodite world spirits are described as a gestalt of the souls of all of the Exodites that have died on the planet and been ritually entrusted to the world spirit's care, exactly as is the case when a soul stone is added to the Infinity Circuit on the Craftworlds. This comparison is made repeatedly in codices, and iirc has been referenced in at least one novel (possibly two).

In short, every bit of fluff about the Exodite world spirits indicates that they are psychic gestalts created and supported by both a series of physical artificial locuses scattered around the world, and the souls of the dead exodites entrusted to their care. Given how psychically inclined the Eldar are, the fact that they can create such a thing is not surprising.

In comparison, the World Spirit of Fenris is an ancient thing (it evidently predates Russ), and humans only interact with it through the Rune Priests. It's unlikely that a world-wide network of structures could exist to support it due to the rather volatile nature of the surface of most of Fenris. Further, the souls of the fenrisian dead are not ritually passed into the care of the spirit. There cannot be a gestalt for the world spirit to build itself around as there are no souls in its care.

What is the Underverse ante-realm but a form of caring for the dead, then?

A.T. wrote:

 Hellebore wrote:
Russ had more background written about him than most primarchs before the Heresy novels started being produced

Curious as to where? I didn't have the 2e wolves codex and he was largely absent from the latter oldhammer books - Ragnar was always the wolf of note in the old days.

Historically Russ was the ass who decided to kill rather than capture Magnus, was strongly against everyone having psykers (except the wolves) supported enforcing the codex (except on the wolves), was MIA for the entire siege of Terra, and then noped out pretty much immediately into the eye of Terror

Except that it was the imminent arrival of the Wolves and Dark Angels' combined forces that prompted Horus to try to lure the Emperor away, the Council of Nikaea only banned sorcery, not psykers, and most definitely never supported enforcing the Codex.

1) the Ultramarines, not the Dark Angels and Wolves

2) yes it did. It dis-established the librarius and banned librarians from using their abilities

3) Russ did oppose breaking up the legions, though

locarno24 wrote:
Russ did oppose breaking up the legions, though

He went both ways, opposing it initially but then signing on Dorn backed out leading to the creation of the compliant Wolf Brothers chapter - kind of a reverse Black Templars approach.

As an on topic tangent, I also don't like the crappification of the daemon primarchs.

HH's need to make the primarchs all super god beings that are tragic(TM) decided that undermining the entire lure of chaos would be a good idea....

ie, they've retconned the daemon primarchs as being idiots who took downgrades rather than sticking with emperor juice that makes them the bestest eva.

The literal whole entire philosophical point and allure of chaos is the sacrificing of your immortal soul for immediate temporal power. That the daemon primarchs unequivocally gained massive power by accepting damnation. Instead because primarchs are the avengers of 40k now and the entire setting has to revolve around them as the protagonists, they are all super beings that have secret powers that they could tap if they just didn't give it up to get chaos power.

And because they're so important as protagonists, they're not really bad, because their bodies got possessed my daemons instead, so GW can resurrect good versions so fans don't feel bad their pet primarchs were evil.

That they took primarch agency away when they became daemons is even more egregious.

The consequences of needing primarchs to be more ridiculous than they used to be and building a retconned background that made them sympathetic so you can't have them really be bad, no taht would make people feel bad about liking them.

No the emperor can just build their souls new bodies and they're all good again, no guilt over taking temporal power in exchange for the soul, it wasn't their fault dad!

I find it actually distasteful that they did this.

In the Trial of Magnus, it is clear that most of the key witnesses are space wolves, probably directed by their primarch Leman Russ to testify against Magnus.

The Trial had the emperor declare that Librarians were outlawed and warp powers were banned. Magnus and the Thousand Sons were driven to chaos and genocided based on this prosecution (and persecution).

3 seconds later the Emperor would be crippled. And immediately most Space Marine chapters started using librarians, and they all use warp magic like nothing during the next ten thousand years, right after alleging it was the epitome of evil and having it banned by the Emprah in person (another massive hypocrite given he taught Magnus about the warp himself, and is/was the galaxy's most powerful psyker).

Not Space Wolves though, they don't have librarians... because they have rUnE pRiEsTs, which is exactly the same (and even with the same psyker powers and rules), just 100% more hypocritical on all counts.

So yeah, there's no way Leman Russ isn't an ass, no matter how many times he "failed" or not.

 Hellebore wrote:
As an on topic tangent, I also don't like the crappification of the daemon primarchs.

HH's need to make the primarchs all super god beings that are tragic(TM) decided that undermining the entire lure of chaos would be a good idea....

ie, they've retconned the daemon primarchs as being idiots who took downgrades rather than sticking with emperor juice that makes them the bestest eva.

The literal whole entire philosophical point and allure of chaos is the sacrificing of your immortal soul for immediate temporal power. That the daemon primarchs unequivocally gained massive power by accepting damnation. Instead because primarchs are the avengers of 40k now and the entire setting has to revolve around them as the protagonists, they are all super beings that have secret powers that they could tap if they just didn't give it up to get chaos power.

And because they're so important as protagonists, they're not really bad, because their bodies got possessed my daemons instead, so GW can resurrect good versions so fans don't feel bad their pet primarchs were evil.

That they took primarch agency away when they became daemons is even more egregious.

The consequences of needing primarchs to be more ridiculous than they used to be and building a retconned background that made them sympathetic so you can't have them really be bad, no taht would make people feel bad about liking them.

No the emperor can just build their souls new bodies and they're all good again, no guilt over taking temporal power in exchange for the soul, it wasn't their fault dad!

I find it actually distasteful that they did this.

Personally, I like that becoming a daemon prince is a sidegrade for Primarchs. I think lore for daemon princes has had it be a double-edged sword for decades. The lure of Chaos is supposed to be a trap- you can obtain enormous power, but it always comes at a cost- aligned princes are bound to the will of their patron god and pay a price in independence (I think this still happens to unaligned princes to a lesser degree), and all princes become detached from the mortal realm and struggle to maintain an interest and/or presence in realspace. They have also frequently made a web of Faustian bargains etc. to reach that point, and risk much if they renege. Chaos is not a game you can win*, but it always pretends you can.

It is the core reason Abaddon has resisted daemonhood for 10000 years, despite having reached the point he could ascend many times over. Apotheosis is not cost-free.

The stuff about other primarchs I agree with though, but that is a symptom of modern GW writing reading like a DC comic.


*Ok, one being did somewhat win, but Be'lakor is specifically noted as an early exception deemed an unrepeatable mistake due to his complete independence.

I have no problem with the double edged sword, but gw have basically pulled any positives out of the bargain.

Every daemonic primarch in the siege of terra was slapped silly by a non daemon powered primarch. And then 10k years later guilliman and lion slap them again.


The bargain was that they gained massive power, primarchs plus ultra. Before the HH novel series the only primarchs that appeared in the game were the 4 daemon primarchs. In epic they were titan equivalents.

They were forces of nature that were terrifying but utterly damned.

100 grey knights were required to banish angron in just one instance.

Now the prose literally has the loyalists laughing at the losers for willingly making themselves less powerful and then just humiliating them with empra power.

It just fails to show why taking the Faustian bargain has any upsides - loyalists are now immortal (they weren't in 2nd) so that's not a perk, loyalists don't need daemon juice to have enough power to best down a daemon primarchs, so there's no perk there, loyalists all have seceret super powers that they develop that was the plan all along (TM), so daemon powers aren't a perk.

They completely undercut the prize of chaos damnation and thereby making a joke out of the temptation. It just says chaos are idiots for taking the deal, not ruthless people prepared to sacrifice their souls for godlike power.

The allure is that chaos delivers on its promise of power, they actually follow through. There is a catch and downsides by damn if you aren't a demigod regardless.

Now that the primarchs are already super demigods, they decided that their power boost was to idiocy and lameness.

 Hellebore wrote:
I have no problem with the double edged sword, but gw have basically pulled any positives out of the bargain.

Every daemonic primarch in the siege of terra was slapped silly by a non daemon powered primarch. And then 10k years later guilliman and lion slap them again.


The bargain was that they gained massive power, primarchs plus ultra. Before the HH novel series the only primarchs that appeared in the game were the 4 daemon primarchs. In epic they were titan equivalents.

They were forces of nature that were terrifying but utterly damned.

100 grey knights were required to banish angron in just one instance.

Now the prose literally has the loyalists laughing at the losers for willingly making themselves less powerful and then just humiliating them with empra power.

It just fails to show why taking the Faustian bargain has any upsides - loyalists are now immortal (they weren't in 2nd) so that's not a perk, loyalists don't need daemon juice to have enough power to best down a daemon primarchs, so there's no perk there, loyalists all have seceret super powers that they develop that was the plan all along (TM), so daemon powers aren't a perk.

They completely undercut the prize of chaos damnation and thereby making a joke out of the temptation. It just says chaos are idiots for taking the deal, not ruthless people prepared to sacrifice their souls for godlike power.

The allure is that chaos delivers on its promise of power, they actually follow through. There is a catch and downsides by damn if you aren't a demigod regardless.

Now that the primarchs are already super demigods, they decided that their power boost was to idiocy and lameness.

Thats an issue with how the loyalist Primarchs have been written, not the Daemon Primarchs. You won't find any disagreement from me that writing the HH novels was a mistake, as was bring the loyalist Primarchs back into 40k. I do think that loyalist Primarchs should be able to beat Daemon ones, but not by being a bigger beatstick, that is obviously silly. Instead, they should have to work around the Daemon strengths and instead use strategies to target their weaknesses, like rage baiting Angron into a trap where he is banished by massive numbers or using Magnus's arrogant overconfidence against him. Which is a tougher ask (and also tougher to write convincingly).

 Hellebore wrote:
Every daemonic primarch in the siege of terra was slapped silly by a non daemon powered primarch. And then 10k years later guilliman and lion slap them again.

Stories of the loyalist Primarchs conquests were certainly fewer before the Heresy book filled them out for content.

Russ stabbing Magnus was about the highlight of the early loyalists success - the rest was filled out with the Lion having a somewhat indecisive fate against Luther, Sanguinius being broken by a daemon and then killed by Horus, Manus was killed early on by Fulgrim who went on to mortally wound Guilliman, Dorn was killed by mooks, Corax went mad, and both Vulkan and Khan bailed without any notable victories.

No decapitating titans and bulldozing legions single handedly, at least not for the loyalists as back then the reference for a daemon primarchs power was epic 40k and the occasional 'banished to the warp after slaughtering all but one of the thousand grey knights who were the only thing that could slow them down'.

I agree with the sentiments made above about the older lore re: Daemon Primarchs vs. Primarchs was better. Chaos = sell your soul for ultimate power (or spawndom!), while the loyaliat Primarchs were great leaders, but ultimately mortals who have been lost.

And that was mirrored in the troops too. Chaos marines could be quite a bit better than the loyalist ones by various measures, with the notable exception of discipline, particularly in the form of self sacrifice for their brothers.

NimoStar wrote:
The Trial had the emperor declare that Librarians were outlawed and warp powers were banned. Magnus and the Thousand Sons were driven to chaos and genocided based on this prosecution (and persecution).

How's it feel over there in the Mirror Universe?

Yes, the edict was passed which banned the practice of psychic abilities, but had Magnus actually, y'know, done as instructed then what happened to the Thousand Sons could've been avoided.

When your Emperor/Father tells you not to do something due to the danger it poses, the correct answer is not to double-down in secret. Especially when you've pledged to obey.

One of the first things Magnus does after being found is to make a deal with a Daemon to halt the flesh curse. He was walking down a dark road from the first day he was discovered, and his arrogance (combined with Chaos' plans to remove him as a threat, admittedly) made matters far worse than they needed to be.

I'd mention the warp-spirits that the Thousand Sons used as a source of knowledge, but I cannae remember the term offhand, so couldn't confirm.

Interesting as well that you lay the blame for Nikaea at the feet of Leman Russ along, when Mortarion, Dorn and Corvus Corax are all directly involved in lobbying for the Emperor to made a decision on the topic - and, in the write-up on Lexicanum I just skimmed, it doesn't sound like Russ provided direct testimony himself. Again, the only Primarch referenced there as speaking is Mortarion (though not all speakers are individually listed in that write-up.

Tutelaries, familiars essentially that turned out to be actual full-on Daemons that ended up possessing a bunch of the Legion during the Burning of Prospero.

As for Nikea, Russ sent emissaries in his stead, like the Khan.
The primary speaker for the Wolves was Othere Wyrdmake, who had spoken at length with Ahriman about the practices of the Thousand Sons, which in turn was used as evidence against them at the gathering.

How's it feel over there in the Mirror Universe?

Yes, the edict was passed which banned the practice of psychic abilities, but had Magnus actually, y'know, done as instructed then what happened to the Thousand Sons could've been avoided.

Why should he have been done as instructed when all the other ones disobeyed the directive as soon as the emperor wasnt there to reprimand them (at the LATEST). So how can one say that Magnus deserved the Nikaea when it happened, if the prohibition extended to what everyone else continued doing for ten millenia. Shouldn't they have been destroyed as well?

Furthermore, in another bout of hypocrisy, both the rest of the chapters and the lore itself states that Librarians and the rest of sanctioned psykers are *THE BEST PROTECTION AND COUNTER* against Chaos itself.

 Insectum7 wrote:
I agree with the sentiments made above about the older lore re: Daemon Primarchs vs. Primarchs was better. Chaos = sell your soul for ultimate power (or spawndom!), while the loyaliat Primarchs were great leaders, but ultimately mortals who have been lost.

And that was mirrored in the troops too. Chaos marines could be quite a bit better than the loyalist ones by various measures, with the notable exception of discipline, particularly in the form of self sacrifice for their brothers.

I don't mind them amping primarchs up a bit, they just need to show that the chaos primarchs actually gained something over their brothers so that it doesn't make them look like chumps.

Chaos as it originally began was very cthulhuian. But it's starting to look more standard 'deal with the devil', where you just get boned because you think you can outsmart the devil. It appears to be becoming a lot more christian parable than unknowable lovecraftian terror from the deep that will grant power but at a cost.


GW have entirely forgotten that the strength of your heroic figures lies almost entirely in the threat of your antagonists. Without that, you just have what looks like kids one upping each other with 'nuh uh, mine has super smash'...


This is what happened to the Avatar 20 years ago, which has somehow been recovering from that, or at least it hasn't been on the receiving end of a lot of Ls in current lore. But maybe that's just because GW have given up on writing any lore that isn't about a marine killing someone else's faction 10 different ways for 300 pages.

NimoStar wrote:
Why should he have been done as instructed when all the other ones disobeyed the directive as soon as the emperor wasnt there to reprimand them (at the LATEST). So how can one say that Magnus deserved the Nikaea when it happened, if the prohibition extended to what everyone else continued doing for ten millenia. Shouldn't they have been destroyed as well?

Furthermore, in another bout of hypocrisy, both the rest of the chapters and the lore itself states that Librarians and the rest of sanctioned psykers are *THE BEST PROTECTION AND COUNTER* against Chaos itself.

Because none of the other Legions broke the Edicts before the Heresy began, at least not publicly like Magnus and the XVth did.

The Khan kept his Stormseers by staying as far away from the powers that be as possible.
Angron never cared about the Edict so the XIIth's Librarians, who were already dying off with no replacement, just kept going.

And yes the entire Edict is hypocritical, that's the point and it's why Magnus was so angry about it.
That doesn't absolve him from enacting a sacrificial ritual to break the wards of the Imperial Palace to warn the Emperor of the coming Heresy, only for it to backfire because unsurprisingly Magnus did not know everything about psychic powers and how sorcery is actually a big no-no for a very good reason.

The Edict stopped being relevant after the Emperor fell and while it was technically never revoked, it served the new Imperium better to just pretend it didn't matter anymore, which again is the whole point. The Imperium is hypocritical.

The "before the heresy began" is a lame ass excuse. Before the Heresy began, chaos was actually much less of a threat. So why is dealing with Warp powers before the Heresy such a major anathema, but after we have daemonic rifts and such all over the galaxy, suddenly it is OK?

Magnus was wronged, and there's no way around it. If he was going too far with the research maybe some observers could have been posted on Prospero and other safeguards. Forcing him to go under and then burning everything down was not only wrong, it was also stupid. As it is, they became another Traitor Legion without even wanting to. Primarchs and the emprah were massively incompetent, since otherwise Magnus would have used his psykers and knowledge of the Warp for mankind, as was his intention from the start.

Although I agree with OP that the current Chaos is lame, and that the current lore goes too much into moralistic christianity, Leman Russ was always a bigoted fanatic; at the same time, his soldiers regularly becoming bloodthirsty monsters doesn't warrant him any reflection.

The Primarchs being not-so-bad, even the traitor ones, I think is warranted on the old version of the lore, to show how the Emperor was an ass too, and the Imperium of Mankind was kind of stupid even in thw "good old days" (some writers say that the Emperor's fiery persecution of all discipline-focused religion is what made humanity vulnerable to chaos in the first place).

Is there ever a reason given why The Emperor never told Magnus’ lads to not use their Tutor Familiars?

It's really just another indicator that the Emperor was really dumb when it came to people skills. He has ZERO trust in his sons and expected them to just obey him without question.

Now, on the one hand, that was the correct path. If they had all done that things would have worked out. On the other, they were never going to do that and the Emperor was naive for not thinking that they might have some problems after the Chaos gods spirited the Primarchs away.

At the very least, the Emperor should have taken Magnus on as a full psychic disciple and trained him properly instead of just trying to keep a lid on things. The cat was out of the bag in terms of psykers being out and about, so the Emperor thinking he could have total control over everything without at least having his sons on board helping was kinda dumb.

That said, an immortal nearly all powerful being being out of touch with more human emotions and decision making would make sense. So the Emperor forgetting that everyone besides himself is an irrational being could be seen as perfectly logical.