Did the Emperor not know that Alpharius / Omegon were twins?

[Valkia the Bloody]

I am making my way through a re-listen to the Horus Heresy audiobooks (and also listening to some of the books I have not read before).

I just finished the First Heretic. 

One thing that has vexed me years ago when the book came out, and is now vexing me again, is the scene of Argel Tal looking at the Primarch pod of the Alpha Legion and seeing the twins. 

In some of the later Horus Heresy books, as well as the Alpharius novel, it seems to be a massive secret that there were twins. 

For example, in Pretorian of Dorn, the Imperial defenders do not know about the twins. 

It just makes no sense to me.

Does the Emperor not have eyes in his head? Did the Emperor know but not tell anyone as some kind of in-joke and later forgot for some reason?

Did none of his breeding science minions realize that one of the Primarch pods needed twice the nutrients and produced twice the waste? Or were they not fed because space-magic? Or are Primarchs like ant larvae that do not produce waste and store it in a sack inside the body until they are born?

Did they fire the wet-nurse before she could spill the beans?

What is going on here? 

Please enlighten me. 

 

[SvenIronhand]

As always with the XXth, it's a riddle wrapped in an enigma.

[Valkia the Bloody]

Of course it could just be a plot-hole that was forgotten to fill. 

[Blissful Brushes]

53 minutes ago, Valkia the Bloody said:

Of course it could just be a plot-hole that was forgotten to fill. 

As brilliant as the HH stuff is, it’s probably 75% plot hole, at least the earlier works.

[Karhedron]

We simply don't know if the Emperor knew or not. If he did, it seems he didn't tell the other Primarchs, even after the AL sided with Horus.

 

Alpharius' Primarch novel doesn't reall clarify much. It is not clear if the twins were deliberately created or if the XX Primarch embryo was split during the scattering. Omegon crash-landed back on Terra in half a pod, just a few hundred miles from the Imperial Palace and was quickly recovered by the Emperor. The Emperor was busy preparing the Great Crusade so much of his early training fell to Malcador which probably explains the Legion's fondness for obfuscation and deception. 

[SlickSamos]

On 2/18/2026 at 9:42 PM, Valkia the Bloody said:

One thing that has vexed me years ago when the book came out, and is now vexing me again, is the scene of Argel Tal looking at the Primarch pod of the Alpha Legion and seeing the twins. 

 

To confuse this further, the Warp chose to show Argel Tal what they wanted him to see, it was a vision not reality/history.  So the whole splitting after the scattering can still be true etc...

 

My guess is that the Warp chose to slip the secret to the XVIIth to give them another advantage. (Edit) - whether or not they had split before or after the scattering.  (whether or not any of this was thought through by the authors at the time though is a different matter)

Edited February 21 by SlickSamos

[DuskRaider]

On 2/19/2026 at 4:12 PM, Karhedron said:

We simply don't know if the Emperor knew or not. If he did, it seems he didn't tell the other Primarchs, even after the AL sided with Horus.

 

Alpharius' Primarch novel doesn't reall clarify much. It is not clear if the twins were deliberately created or if the XX Primarch embryo was split during the scattering. Omegon crash-landed back on Terra in half a pod, just a few hundred miles from the Imperial Palace and was quickly recovered by the Emperor. The Emperor was busy preparing the Great Crusade so much of his early training fell to Malcador which probably explains the Legion's fondness for obfuscation and deception. 

I’ve read a theory that Alpharius was / is a Perpetual akin to Vulcan (part of the Trefoil, which would imply Russ is as well). Any time he dies, a copy is created with a portion of his soul. Obviously just theory crafting, but it would explain how Omegon came to be and would cause some interesting implications. 
 

That being said, yes the Emperor knew of Omegon. He implied as much when he and Malcador were playing Regicide and possessed two Hydra pieces. 
 

There’s a good chance that what Argel Tal saw was also just created by Chaos and not real at all, kinda like when Horus saw the Primarchs in their incubators during his “vision quest”. 

[calgar101]

I don't believe Alpharius was a perpetual, but I find it hard to find the Emperor wouldn't know. Weren't Alpharius/Omegon described as one soul spilt in two bodies? Being one of the Trefoil to me, would be because they are twins. Then the Emperor and Primarch's had some warp connection? Surely he would feel there was twin Primarchs? 

[Karhedron]

18 minutes ago, calgar101 said:

I don't believe Alpharius was a perpetual, but I find it hard to find the Emperor wouldn't know. Weren't Alpharius/Omegon described as one soul spilt in two bodies? Being one of the Trefoil to me, would be because they are twins. Then the Emperor and Primarch's had some warp connection? Surely he would feel there was twin Primarchs? 

 

I agree that Alpharius was not a Perpetual. As to whether the Emperor knew, I am just going off what was in print. Omegon was discovered well into the GC and the twins then staged Alpharius' discovery by Horus as the last Primarch found. They went to considerable lengths to keep the twin secret within the Legion. There is nothing to indicate they ever told the Emperor

 

Did the Emperor know? It is never stated one way or the other. Part of it depends on whether they were intentionally twins or whether a single embryo was split when the Primarchs were scattered. Relying on warp connections for knowledge is always risky. The Emperor should have known Lorgar was talking to the Chaos in the decades between Monarchia and Davin but apparently did not.

 

As to the Trefoil Legions, I had always taken their separate training to be because of the role of the Legions rather than their Primarchs specifically:

• Space Wolves - Keeping the other Legions in line
• Salamanders - Humanitarian aid
• Alpha Legion - Covert and Psy-Ops

[SlickSamos]

15 hours ago, Karhedron said:

• Space Wolves - Keeping the other Legions in line
• Salamanders - Humanitarian aid
• Alpha Legion - Covert and Psy-Ops

 

Arbitor Ian (a man who knows more than I) would argue that they were because of:

Space Wolves - Canis Helix experiment 

Salamanders - Vulkan being a Perpetual and his eternal warden

Alpha Legion - covert internal security against other legions and other threats (and were only forced to show them selves for the Rangdan Xenocides)

 

16 hours ago, calgar101 said:

Then the Emperor and Primarch's had some warp connection?

 

I don't think so?  Some had foresight or visions of him before being reunited but that doesn't mean it was a connection.  Magnus is the only one who claimed to 'speak to his father' for his whole life but given who he eventually fell to serve, did he?

[calgar101]

That's why I used a ? as I wasn't saying they had a warp connection but could one exist. Those legions/Primarchs of the Trefoil had something 'extra' about them. Canis Helix for the Wolves, Vulkan being a Perpetual. Perhaps the Alpha Legion's 'ability' wasn't twin Primarchs but being able to pass of as their Primarch? 

[Gorgoff]

On 2/18/2026 at 10:42 PM, Valkia the Bloody said:

I am making my way through a re-listen to the Horus Heresy audiobooks (and also listening to some of the books I have not read before).

I just finished the First Heretic. 

One thing that has vexed me years ago when the book came out, and is now vexing me again, is the scene of Argel Tal looking at the Primarch pod of the Alpha Legion and seeing the twins. 

In some of the later Horus Heresy books, as well as the Alpharius novel, it seems to be a massive secret that there were twins. 

For example, in Pretorian of Dorn, the Imperial defenders do not know about the twins. 

It just makes no sense to me.

Does the Emperor not have eyes in his head?

In the Alpharius novel he did not know that, no.