What is the greatest tragedy in the Horus Heresy to you?

[LongGone]

The greatest tragedy is that BL decided they could turn the HH into a perpetual cash cow of limited release novellas and anthologies of reprinted stories while doubling to tripling prices across the board.

Ding! We have a winner.

[Void Knight]

Both Lorgar's and Magnus's fall were the greatest tragedies of the Horus Heresy.  They were two men searching for the truth, but in the end they both ended up following some for of blind faith.

[Frosco Toppings]

I think the greatest tragedy is that the Emperor thought it would be a good idea to create 20 childish part-daemons to lead his legions.

[Jarl Kjaran Coldheart]

the only element of the Horus Heresy I feel sorrow for is Angron. He never had a chance.

 

the rest of them, through greed or ignorance, made their choices.

 

WLK

[Black Cohort]

I think the Emperor was the greatest tragedy of the horus heresy. Incredibly awesome at life, except for being able to relate to people or be a father. If the Emperor had been even a halfway decent father to the Primarchs, most of the issues that led to the heresy never would have come up.

[Legatus]

So, which of the Primarchs had not already been a fully grown adult when the Emperor found them? How does lack of fatherly qualities play any part in this?

[Loesh]

So, which of the Primarchs had not already been a fully grown adult when the Emperor found them? How does lack of fatherly qualities play any part in this?

 

It's not that difficult to discern, all the Primarchs clearly looked to him as a parent adult or not and spent time with him as family.

 

With what can only be described as incomprehensible idiocy he often manages to screw this potential advantage up, the entirety of the Horus Heresy is a product of this father/son relationship.

 

I'm still waiting for rational answers to the Council of Nikaea, Angrons transportation, and Lorgars shaming among a billion tiny mistakes with everyone else that make sense besides he's tyrant, idiot king, lazy, or some combination of all these things. As we get answers to them these answers actually look progressively worse, not better, with layer upon layer heaped into a pyre of spectacular foolishness that even the basic humans in the setting with an iota of common sense could see was a catastrophic mistake.

 

But then again, maybe not knowing is the point as Angron himself said, we'll never know.

[A D-B]

 

So, which of the Primarchs had not already been a fully grown adult when the Emperor found them? How does lack of fatherly qualities play any part in this?

 

It's not that difficult to discern, all the Primarchs clearly looked to him as a parent adult or not and spent time with him as family.

 

With what can only be described as incomprehensible idiocy he often manages to screw this potential advantage up, the entirety of the Horus Heresy is a product of this father/son relationship.

 

I'm still waiting for rational answers to the Council of Nikaea, Angrons transportation, and Lorgars shaming among a billion tiny mistakes with everyone else that make sense besides he's tyrant, idiot king, lazy, or some combination of all these things. As we get answers to them these answers actually look progressively worse, not better, with layer upon layer heaped into a pyre of spectacular foolishness that even the basic humans in the setting with an iota of common sense could see was a catastrophic mistake.

 

But then again, maybe not knowing is the point as Angron himself said, we'll never know.

 

 

I don't see Lorgar's shaming as a mistake. Lorgar's reaction to it undoubtedly led to disaster, but that was Lorgar's choice. The act of chastising Lorgar and the Word Bearers wasn't, in itself, a terrible thing. It was momentous, it was important, and it was unusual. All true. But it was a chastisement to a Legion that continually refused to do as he ordered, and propagated a lie in the Emperor's name. Chastising them for it was a pretty justified move, and only came after repeated warnings to speed up the Great Crusade along with the other Legions, and stop establishing cults of Imperial religion in the Emperor as a God.

 

And even then, it was a chastisement. A shaming, for deeds already done. There's no mystery there. Lorgar chose to disobey the Emperor for years before it happened. You could even say it was ultimately expected. This is what happens when armies disobey. They get punished. Let alone when people disobey a galactic warlord.

 

And even then, he was told to kneel for a few minutes and stop doing what he'd been doing. There's no arguing that the shame was immense, but it was hardly decimation of the Legion or imprisonment of the primarch, as others suffered. Lorgar's nature and the insipid whispers of those manipulating him spurred the primarch on to other things after it. Imagine if they'd helped him get over it and use it as a driving force to do the Emperor's bidding instead, like the other primarchs were.

 

Comparatively, something like Angron's teleportation or the Council of Nikea - they linger in fans' eyes as confusing because the answers aren't obvious or readily available. We can assume why the Emperor teleported Angron away, we can make inferences from what little we have, but there's no definitive answer... or even any obvious ones. Whereas we've known for years that Lorgar's chastisement came because he'd been disobedient for decades. He earned it through his own deeds.

 

I find Lorgar's reaction believable given the context of his upbringing, power, and surroundings. Lorga wasn't all "Daemons are ace! Yay!" when he found out the truth, but the truth was all he sought, and he got it. Just as I find Magnus's reaction believable, when he was so sure he was right to breach the psychic defences around Terra. He damned humanity with that move, and doomed the species to a gradual extinction. (Spoilers: 40K has plainly never been about the Imperium winning. That chance came in 30K, and humanity blew it. That's the point.)

 

EDIT: But I think sometimes there's a danger of forgetting just who the Emperor is, in all this. He's an immortal superscientist genius with a god's powers who systematically pulled a Genghis Khan on every other culture and nation on his planet, forcing them to join him or annihilating them. Then he turned that attitude on the galaxy. And, just like any tyrant, he did it because he was apparently sure it was for the best. No one who does truly evil things thinks they're evil. They're doing it for reasons that they ultimately think are for the betterment of those people that matter. The road to Hell is paved with... Well, you know the rest. Let's just say he didn't make over a million Space Marines and send them on a "crusade" because he thought violence against those that disagreed with him was wrong.

 

And none of that's any insight into his nature, really. That's just what we know he did; the setting exists because of it.

[BNG1991]

To me, the greatest tragedy is the fate of Interex. Granted, their overall power as an space-faring nation was not enough to sustain the constant war in the far off future. But their greatest weapon was their doctrine against Chaos influence, instead of military prowess.

 

When you compare the Imperium's propaganda of 'Ignorance is blessing' to Interex's belief 'educate the folks so that nobody tempt Kaos', you could see what I mean. And they could be a better fighters. What a waste of potential...

 

BTW, where should I post the theory of Terra's original owner in this forum?

[Aralon56]

The loss of Koriel Zeth.

[GoogleusMaximus]

I think for the Emperor Nikea makes perfect sense when you read the books and look at the manipulations that occurred.

He knew that Magnus was delving too deep in the warp and might have been aware that some kind of sorcery was used to stop the mutations. Likely he just wanted to find a way to reign his son in and keep him from being completely corrupted before he finished the webway project. Personal theory mind you but it makes sense to me.

As for Angron... I am not sure and don't even have a real theory.

[Iron Father Ferrum]

For me, the greatest tragedy is how Ferrus died.  Not that he died, but how.  For all our talk about how the Emperor failed as a father-figure to his sons, you also have to remember that the Primarchs viewed each other as brothers.  Not as a brotherhood with an inducted membership, but as flesh-and-blood brothers.  Brothers squabble and fight.  They nurse grudges and bring them up at family gatherings year after year.  Each of the Primarchs had their squabbles with particular other Primarchs, and these rivalries blew up in the galaxy's collective face at the onset of the Heresy.

 

But some of these brothers were close.  Super close.  "Best man at my wedding" close, even. This sort of relationship appears to have been sadly less common than the personality clashes that we all know and love, but one such relationship stands out: Ferrus and Fulgrim.  Ferrus Manus was the ugliest Primarch, but was massive in proportion.  Like a volcano, he was sturdy and imposing but capable of bouts of incredible rage.  And Fulgrim, one of the Primarchs who was the furthest from Ferrus in looks, temperament, and outlook, became his best friend.  Imagine if Erwin Rommel (tactically brilliant, a risk-taker, but who tended to overstep his bounds) and Bernard Montgomery (risk-averse, preferential of attrition warfare) grew up together as next-door neighbors and became the best of friends throughout their lives.  That was Ferrus and Fulgrim, the Odd Couple of the Primarchs.

 

And it is Fulgrim who killed Ferrus.

 

Say what you want about daemons and the Laer blade and their corrupting influence at the final moment.  But Fulgrim was himself when he chose Horus.  Fulgrim was himself when he promised he could turn Ferrus.  Fulgrim was himself when he tried and failed to do so.  Fulgrim was himself when he left Ferrus bloody and concussed on the floor of the Anvilarium.  Fulgrim was himself when he Ferrus crossed blades on the black sands of Istvaan V.  He knew what he was doing.  The moment Ferrus turned him down, he knew that they would fight to the death eventually.  Fulgrim betrayed his closest brother, knowingly and on purpose, and committed to a cause that had only one logical conclusion for his friendship with Ferrus.

 

I don't mourn the death of Ferrus Manus.  I mourn the death of his friendship with Fulgrim.

[Carrack]

The problem I have with Angron, and to an extent Curze, is not that their story is tragic. I find them too unsympathetic to view them as tragic. The problem I have is why were they used in the first place. Both seem to me as being driven into the camp of the traitors by the commonly held view of their legions' methods, but it's not as if this was a great surprise to anyone. Both primarchs and their legions had been conquering, or depopulating, worlds using these methods for a while, before the rest of the Imperium condemned their actions, so what changed? Also, was the Emperor so short on generals that he needed to give legions to Angron and Curze, it's not as if the methods they would use in war should have surprised anyone?

[Void Knight]

For me, the greatest tragedy is how Ferrus died.  Not that he died, but how.  For all our talk about how the Emperor failed as a father-figure to his sons, you also have to remember that the Primarchs viewed each other as brothers.  Not as a brotherhood with an inducted membership, but as flesh-and-blood brothers.  Brothers squabble and fight.  They nurse grudges and bring them up at family gatherings year after year.  Each of the Primarchs had their squabbles with particular other Primarchs, and these rivalries blew up in the galaxy's collective face at the onset of the Heresy.

 

But some of these brothers were close.  Super close.  "Best man at my wedding" close, even. This sort of relationship appears to have been sadly less common than the personality clashes that we all know and love, but one such relationship stands out: Ferrus and Fulgrim.  Ferrus Manus was the ugliest Primarch, but was massive in proportion.  Like a volcano, he was sturdy and imposing but capable of bouts of incredible rage.  And Fulgrim, one of the Primarchs who was the furthest from Ferrus in looks, temperament, and outlook, became his best friend.  Imagine if Erwin Rommel (tactically brilliant, a risk-taker, but who tended to overstep his bounds) and Bernard Montgomery (risk-averse, preferential of attrition warfare) grew up together as next-door neighbors and became the best of friends throughout their lives.  That was Ferrus and Fulgrim, the Odd Couple of the Primarchs.

 

And it is Fulgrim who killed Ferrus.

 

Say what you want about daemons and the Laer blade and their corrupting influence at the final moment.  But Fulgrim was himself when he chose Horus.  Fulgrim was himself when he promised he could turn Ferrus.  Fulgrim was himself when he tried and failed to do so.  Fulgrim was himself when he left Ferrus bloody and concussed on the floor of the Anvilarium.  Fulgrim was himself when he Ferrus crossed blades on the black sands of Istvaan V.  He knew what he was doing.  The moment Ferrus turned him down, he knew that they would fight to the death eventually.  Fulgrim betrayed his closest brother, knowingly and on purpose, and committed to a cause that had only one logical conclusion for his friendship with Ferrus.

 

I don't mourn the death of Ferrus Manus.  I mourn the death of his friendship with Fulgrim.

The Horus Heresy is all about brother fighting brother.

 

It's in the metaphorical sense when it comes to the fighting between the Legions.  But a Primarch fighting another Primarch is literally brothers trying to killing each other.

 

This being true, then the Horus Heresy never began on Isstvan III, it began on Isstvan V.  Some would that it is the betrayal of the Dropsite Massacre that started the Heresy, but I think it's more heartbreaking to believe that the Heresy began when a brother murdered the brother he was closest to, for the simple reason of "because he can."

[Flint13]

the only element of the Horus Heresy I feel sorrow for is Angron. He never had a chance.

the rest of them, through greed or ignorance, made their choices.

WLK

Right? He essentially woke up into his own personal hell which he could never escape from.

The one single joy of his tortured life, the camaraderie shared by his brothers and sisters, was torn from him in a jerk-bag power move from the Emperor. Not only that, he knew that had he been there, he could have either changed the outcome of De'shea or died happy, fighting alongside those he loved (or at least as close to the emotion as his damaged psyche could approximate) and finally released from the wracking agony of the original Butcher's Nails.

Worse still, upon his return, he came to find the planet's entire populace thought him a coward who had abandoned his blood bound family to an unwinnable slaughter.

Everyone he loved died, and they died hating him.

Meanwhile, the Emperor can spend weeks dicking around in the mountains of Nocturne with Vulkan on a giant lizard scavenger hunt

[Jarl Kjaran Coldheart]

the only element of the Horus Heresy I feel sorrow for is Angron. He never had a chance.

the rest of them, through greed or ignorance, made their choices.

WLK

Right? He essentially woke up into his own personal hell which he could never escape from.

The one single joy of his tortured life, the camaraderie shared by his brothers and sisters, was torn from him in a jerk-bag power move from the Emperor. Not only that, he knew that had he been there, he could have either changed the outcome of De'shea or died happy, fighting alongside those he loved (or at least as close to the emotion as his damaged psyche could approximate) and finally released from the wracking agony of the original Butcher's Nails.

Worse still, upon his return, he came to find the planet's entire populace thought him a coward who had abandoned his blood bound family to an unwinnable slaughter.

Everyone he loved died, and they died hating him.

Meanwhile, the Emperor can spend weeks dicking around in the mountains of Nocturne with Vulkan on a giant lizard scavenger hunt

Agreed.

What I dont understand is WHY?

The Emperor is a being with virtually unlimited levels of power.

His Custodes are almost warriors without peer.

His naval fleets could have bombarded the Slavers army without risk.

Why couldnt the Emperor lay righteous amounts of Whoop-Ass tm on those primitive screwheads??

Poor writing, and much like Nikea, something I wished BL would have addressed but ended up dropping the ball.

WLK

[Loesh]

 

I don't see Lorgar's shaming as a mistake. Lorgar's reaction to it undoubtedly led to disaster, but that was Lorgar's choice. The act of chastising Lorgar and the Word Bearers wasn't, in itself, a terrible thing. It was momentous, it was important, and it was unusual. All true. But it was a chastisement to a Legion that continually refused to do as he ordered, and propagated a lie in the Emperor's name. Chastising them for it was a pretty justified move, and only came after repeated warnings to speed up the Great Crusade along with the other Legions, and stop establishing cults of Imperial religion in the Emperor as a God.

 

And even then, it was a chastisement. A shaming, for deeds already done. There's no mystery there. Lorgar chose to disobey the Emperor for years before it happened. You could even say it was ultimately expected. This is what happens when armies disobey. They get punished. Let alone when people disobey a galactic warlord.

 

And even then, he was told to kneel for a few minutes and stop doing what he'd been doing. There's no arguing that the shame was immense, but it was hardly decimation of the Legion or imprisonment of the primarch, as others suffered. Lorgar's nature and the insipid whispers of those manipulating him spurred the primarch on to other things after it. Imagine if they'd helped him get over it and use it as a driving force to do the Emperor's bidding instead, like the other primarchs were.

 

Comparatively, something like Angron's teleportation or the Council of Nikea - they linger in fans' eyes as confusing because the answers aren't obvious or readily available. We can assume why the Emperor teleported Angron away, we can make inferences from what little we have, but there's no definitive answer... or even any obvious ones. Whereas we've known for years that Lorgar's chastisement came because he'd been disobedient for decades. He earned it through his own deeds.

 

I find Lorgar's reaction believable given the context of his upbringing, power, and surroundings. Lorga wasn't all "Daemons are ace! Yay!" when he found out the truth, but the truth was all he sought, and he got it. Just as I find Magnus's reaction believable, when he was so sure he was right to breach the psychic defences around Terra. He damned humanity with that move, and doomed the species to a gradual extinction. (Spoilers: 40K has plainly never been about the Imperium winning. That chance came in 30K, and humanity blew it. That's the point.)

 

EDIT: But I think sometimes there's a danger of forgetting just who the Emperor is, in all this. He's an immortal superscientist genius with a god's powers who systematically pulled a Genghis Khan on every other culture and nation on his planet, forcing them to join him or annihilating them. Then he turned that attitude on the galaxy. And, just like any tyrant, he did it because he was apparently sure it was for the best. No one who does truly evil things thinks they're evil. They're doing it for reasons that they ultimately think are for the betterment of those people that matter. The road to Hell is paved with... Well, you know the rest. Let's just say he didn't make over a million Space Marines and send them on a "crusade" because he thought violence against those that disagreed with him was wrong.

 

And none of that's any insight into his nature, really. That's just what we know he did; the setting exists because of it.

 

 

Allow me to structure my thoughts a bit more articulately, the problem is however that I don't see the actual shaming itself as the problem, so much as how it's carried out and the Emperors attitude and apparent mannerisms until then. Because the Emperor does nothing but exude divinity, it's the very reason it's so easy to seem like he's a god on one hand he did give these warnings and it's precisely why I wanted to look at in the context of Lorgar at his worst. Maybe it isn't a mistake, maybe there's some grand plan, and maybe there is a very good and articulate reason for why he can only project this power, maybe he can't even control it as Lorgar falls further and further down that path.

 

But we don't see it is the problem, we don't even really have an inkling of it because we cannot see through the Emperors eyes. I don't want to assume anything about Master of Mankind but I think it'd be fair to say that won't answer all these things either(Nor should it in my opinion.) and this apparent doing of one thing while saying another is what's mysterious to me, as mysterious as just teleporting Angron rather then supporting his army because a simple solution seems to try and tone it down a notch rather then amp it up.

 

Maybe Lorgar wouldn't of even listened then if he didn't appear as this radiant multi-faceted being, but everything the Emperor did seemed to be saturated with the divine.

 

I'm trying to view the setting holistically, knowing everything we know so far and I can't come up with a solid answer. in fact I just come up with more questions. The Emperor cannot be perfect in the same way that no one in the setting can be perfect, and so is it possible he just....overlooked this part of himself entirely? It seems so obvious, at least from a mortal perspective, or even an Astartes perspective, that Lorgar could only be driven to search for faith in the universe when until the very ending of that relationship it seemed there was a being who outwardly rebuked that faith but seemed to be the perfect manifestation of it.

 

I suppose I should rephrase it then: How the Emperor carried out the shaming, and that the shaming itself happened isn't the mistake, but what led up to it seems to be. In the absence of evidence, it's easy to assume the worst as a result.

[A D-B]

the only element of the Horus Heresy I feel sorrow for is Angron. He never had a chance.

the rest of them, through greed or ignorance, made their choices.

WLK

Right? He essentially woke up into his own personal hell which he could never escape from.

The one single joy of his tortured life, the camaraderie shared by his brothers and sisters, was torn from him in a jerk-bag power move from the Emperor. Not only that, he knew that had he been there, he could have either changed the outcome of De'shea or died happy, fighting alongside those he loved (or at least as close to the emotion as his damaged psyche could approximate) and finally released from the wracking agony of the original Butcher's Nails.

Worse still, upon his return, he came to find the planet's entire populace thought him a coward who had abandoned his blood bound family to an unwinnable slaughter.

Everyone he loved died, and they died hating him.

Meanwhile, the Emperor can spend weeks dicking around in the mountains of Nocturne with Vulkan on a giant lizard scavenger hunt

Agreed.

What I dont understand is WHY?

The Emperor is a being with virtually unlimited levels of power.

His Custodes are almost warriors without peer.

His naval fleets could have bombarded the Slavers army without risk.

Why couldnt the Emperor lay righteous amounts of Whoop-Ass tm on those primitive screwheads??

Poor writing, and much like Nikea, something I wished BL would have addressed but ended up dropping the ball.

WLK

There's still time to address it. As far as I'm aware, no one's tried yet. I certainly haven't.

[Jarl Kjaran Coldheart]

the only element of the Horus Heresy I feel sorrow for is Angron. He never had a chance.

the rest of them, through greed or ignorance, made their choices.

WLK

Right? He essentially woke up into his own personal hell which he could never escape from.

The one single joy of his tortured life, the camaraderie shared by his brothers and sisters, was torn from him in a jerk-bag power move from the Emperor. Not only that, he knew that had he been there, he could have either changed the outcome of De'shea or died happy, fighting alongside those he loved (or at least as close to the emotion as his damaged psyche could approximate) and finally released from the wracking agony of the original Butcher's Nails.

Worse still, upon his return, he came to find the planet's entire populace thought him a coward who had abandoned his blood bound family to an unwinnable slaughter.

Everyone he loved died, and they died hating him.

Meanwhile, the Emperor can spend weeks dicking around in the mountains of Nocturne with Vulkan on a giant lizard scavenger hunt

Agreed.

What I dont understand is WHY?

The Emperor is a being with virtually unlimited levels of power.

His Custodes are almost warriors without peer.

His naval fleets could have bombarded the Slavers army without risk.

Why couldnt the Emperor lay righteous amounts of Whoop-Ass tm on those primitive screwheads??

Poor writing, and much like Nikea, something I wished BL would have addressed but ended up dropping the ball.

WLK

There's still time to address it. As far as I'm aware, no one's tried yet. I certainly haven't.

Nothing would make me happier than seeing this addressed.

It's always been one of the things that bugged me the most about the 30k setting.

[Augustus]

Angron is tragic as of now because his kidnapping makes no sense and can be only seen as a horrible horrible move by the Emperor. I wrack my brain all the time to create a plausible scenario to justify what was done to him --to no real success.

It's interesting(read: even more horrible) if you subscribe to the theory that the Emperor knew where they would land or even caused them to land on the planets they did. 

[Mellow]

The thing about Lorgars shaming is not so much his father saying he was wrong. It was the fact that he was jealous of the Ultramarines and having them standing there watching only served to fuel that jealousy further.

 

The HH as a whole is the God, Lucifer and associated Angels storyline, only on a sci fi setting. It's meant to be tragic.

 

For me the worst part of the HH was The Emperor leaving the front lines. Granted he had valid reasons, but his secrecy was unwarranted in some cases (i.e. Even after everything half of his Sons stayed loyal)

[Loesh]

Really the questions to these things are fascinating really because they do at times seem like towering incompetence but it's fun to think of a reason more complicated even if it has no actual backing because it's fun to speculate. Why did the Emperor choose Perturbo to build Nikaea even though Magnus was his closest friend? Simple incompetence? mismanaged paperwork? didn't know about their bond? maybe he knew his sons secret potential and thought he was the only one who could do it to specifications?

 

I think of all the hours wracking my brain of what possible justification the Emperor had for appearing to Lorgar like a god goes something like: "The Warp is a fickle mistress and even if the Emperor despised it, his power was still drawn from it and like all mortals the warp changes and shifts to perception. Regardless of if he made some secret pact with Chaos perhaps it still held some sway over his own perceptions just as it shifted to the perception of others. Where countless people saw a radiant golden god perhaps he looked in the mirror and simply saw a man in some particular ornate armor and dismissed the claims as the ramblings of the mad or the deluded, perhaps he was so confident in himself that even when his closest advisers said something of the like he merely smiled and shook his head because they did not share his vision."

 

Apologies if I came off as hostile to anyone at all, I do like discussing these things. I just tend to subscribe to Occams Razor and attribute these errors to the Emperor merely not being as perfect as people thought he was, most likely because of my own bias sitting on Chaos side of the fence. But by no means do I think my idea of the Emperor is some holy immutable truth of the setting. 

[1ncarnadine]

 

I'm trying to view the setting holistically, knowing everything we know so far and I can't come up with a solid answer. in fact I just come up with more questions. The Emperor cannot be perfect in the same way that no one in the setting can be perfect, and so is it possible he just....overlooked this part of himself entirely?

 

This has just been my assumption for a long time, but I always figured the Emperor thought he had genetically "programmed" or "perfected" his sons in a way that they couldn't really disobey him. The time he spent with some of them was to teach them things that he needed to spend that time to teach, and the others he just thought ok, whatevs, they'll do what I intended as they are.

 

The real failing being that he assumed human nature wouldn't overpower his work, except that his work was by a human. Maybe the mostly psychically powerful super-human ever, but still.

 

Like, the triumph of the human condition, but the failure of the human race, I guess?

[Legatus]

There is a simple and obvious explanation for why the Emperor teleported out Angron instead of "helping" him. But in this universe of constand genocidal wars it may not be occurring to everyone. The Emperor made the decision to NOT condemn a striving and powerful civilisation (which might have been vital for the stability of the entire region) to extinction, only to save one individual. Especially since he did have the means to save said individual without any additional bloodshed.

 

Without the Emperor's intervention, the entire slave army and Angron would be slain. With "full" intervention, the entire world would burn. The Emperor decided to remove just Angron from the picture. Events played out exactly as if the Emperor had not been there at all. The slave army was slain. Just Angron was spared. It hurt Angrons pride, but it was the least intrusive and destructive solution.

 

The Emperor then gave Angron an army so powerful that he could continue to fight against injustice on thousands and more worlds. He just didn't imagine that Angron would come to the conclusion that the Emperor himself was unjust, his vision swayed by Horus and his reason clouded by his cybernetic implants.

[Flint13]

I think "hurting Angron's pride" is a gross oversimplification of having to watch his entire adopted family murdered.

 

Was the very temporary preservation of the infrastructure of Angron's home planet worth the psychological murder and eventual rebellion of one of his most martial sons? I can see the point you're trying to make there, but it doesn't hold water for me. What is a single planet measured against the loyalty of your arguably most vicious and weaponized primarch?

 

Alternative solution: Help Angron liberate the planet and save his adopted family, which is literally the only thing he cares about. The planet itself burns (as it does the very day Angron returns to it) but Angron no longer has a reason to hate the Emperor. For comparatively minimal effort on the Emperor's part, Angron stays closer to the fold now because after displaying his martial strength and the importance he places on blood ties, the Emperor is a warrior that Angron can respect. Hell, what would the heresy have been like if Angron remained loyal? Goddamn Horus was wary of fighting him. That's a bro you want on your side. I suppose you could argue that Angron's condition would have pushed him traitor eventually, but at the very least the Emperor would have had one less rebellious super weapon in the earlier days of the Crusade. Might have lead to a few less (thousands) dismembered Ultramarines later down the line in the Shadow Crusade too.

 

I suppose too there could be an argument made that the Emperor didn't know the full extent of the hatred his actions would inspire in Angron, but that seems kinda lame considering all of his otherwise far reaching antics.