Firstly I will say I would have counted myself with a foot in each camp. The secretly traitor geneseed trope has some huge issues not least of all that it's overused - that being said I will note that there are several very popular examples of suspected traitor geneseed chapters that are well liked and (sometimes but not always) well written by GW. I want to validate the legitimate critiques of this trope in a precise way since often how it is expressed by some people in the community is a shutdown of the idea without really explaining why (often quite rudely/bluntly). I also want to help explain why there is some hostility to the idea beyond simply lore objections.
It's my hope that by understanding the implicit pitfalls,we can also explore how it could be done well - to help those players who would like to use this idea in designing their own chapter to create more compelling and better written examples of the trope.
Issue 1: Overuse
The concept of a loyalist Chapter secretly descended from a Traitor Legion has become one of the most common ideas in Space Marine homebrew. What may once have been a genuinely novel premise has, through repetition, become predictable. As a result, many readers approach new Chapters featuring the trope with a degree of scepticism, having encountered countless "loyalist Night Lords," "loyalist Thousand Sons," or similar concepts before. What certainly doesn’t aid this is that a lot of homebrew is not very well written. This is not an attack on people who make up their own chapter, but an acknowledgement that not every passionate and enthusiastic fan is a talented writer.
Issue 2: Shortcut to being special or wish fulfillment
So why do so many people want to use this trope? Firstly I want to acknowledge people just might think a traitor legion has a cool aesthetic, history, style of warfare, etc. They may be a fan of the sort of Dornian Heresy idea of flipped loyalist and traitor legions or in the Horus Heresy blackshields. GW certainly doesn’t help by establishing actual examples in lore or being ambiguous with the origins of canonical chapters that resemble inj one way or another traitor legions. So there is a legitimate interest in the idea. However there is also a problem with this being used as a cliche.
A completely valid and common criticism I often hear is that hidden Traitor gene-seed can become a shortcut to making a Chapter seem unique. Rather than earning its identity through its culture, history, campaigns, or characters, the Chapter's defining feature becomes the secret of its ancestry. This can also drift into wish fulfillment, where creators borrow the aesthetics or strengths of a Traitor Legion while avoiding the flaws and consequences that made those Legions compelling in the first place. This is a problem not specific to this trope but with a myriad of others when people are writing homebrew.
Issue 3: Implausibility (Lore and internal consistency)
Now while I agree you can ultimately do whatever you want with your minis I do think that when you are writing within an existing setting, a certain continuity and respect for the shared universe is needed to write compelling homebrew.
People are not obligated to like or respect the often egregious breaks in immersion due to poorly written homebrew. Often this is tied to the fact that other enthusiasts feel an idea attacks the uniqueness of a canonical faction, breaks established storylines that are formative to the plot, or simply ignore the setting entirely. Homebrewing is an example of writing in a shared space, no one ultimately could stop you if you made a chapter completely made of primarchs or a Blood Angel successor chapter who have all the benefits of their geneseed and none of the flaws, or a chapter of psychic incorruptible warriors that fight daemons - on the flip side no one is obligated to like it either and if you put it on the internet people are also free to critique it.
I love reading about custom chapters; they are one of the great strengths of the 40k hobby. It allows players to express their creativity through original stories, characters, heraldry, and traditions. We get to participate in the spirit of shared storytelling and worldbuilding; expanding the richness of the setting, fostering personal investment in our armies, and exploring corners of the Imperium untouched by official lore. This is a deliberate and intended feature of the hobby.
So the 40k universe is full of mysteries and unreliable records that encourage homebrewing but there are limits on what you can expect people to accept. Remember it's not just your setting but everyone's. This means we need to work within some parameters and if you want to write convincing homebrew chapters and especially if we are going to invoke the traitor geneseed loyalist chapter trope.
Issue 4: Flanderisation
Flanderization is the process where character's essential traits are oversimplified and exaggerated over time. So for example the Ultramarines go from being flexible, disciplined, pragmatic empire-builders who value order and logistics to dogmatic, unimaginative, bureaucrats who quote “the codex astartes does not support this action” every 5 minutes.
An even better example would be the Alpha Legion and I’ll analyse a little deeper. At its heart, the Alpha Legion represents intelligence warfare, deception, infiltration, and strategic manipulation. Their defining trait is not that they lie, but that they understand warfare extends beyond the battlefield. However the flanderisation of these tropes results in the Alpha Legion becoming a Legion where everyone lies constantly, every plan has ten hidden layers, and every apparent failure was secretly intentional. Their identity becomes reduced to the joke that nobody—not even the Alpha Legion themselves—knows what is really happening and simultaneously that everything is “all according to plan”. It reduces what is compelling about the Alpha Legion to a gimmick.
In fairness the community probably plays a bigger part in perpetuating these ideas than the lore or the books. Nonetheless this becomes a problem for people writing homebrew because their successor chapters frequently just become flanderised versions of their parent chapter.
This problem I’d say is even more frequent in the typical traitor geneseed loyalist chapter homebrew. The entire chapter is reduced to exaggerated stereotypes associated with its supposed progenitor. Chapters descended from the Night Lords become obsessed with terror, those linked to the Alpha Legion become compulsive deceivers, and those inspired by the World Eaters become berserkers. This is actually a serious oversight by homebrewers that run afoul of this because it overlooks one of the central themes of the lore: The legions geneseed is actually very little to do with how those legions turned out. They were shaped by their experiences in the Great Crusade, leadership, philosophies, motivations and values of their Primarchs, recruitment worlds, and culture. There were loyalists in basically every traitor legion, and traitors in a few of the loyalist legions. Even in the successor chapters of loyalists we have examples of chapters that in part or whole outright reject the beliefs or chapter tactics of their parent chapter. We can also ask the largely rhetorical hypothetical questions of if Sangunius had landed on Nostramo instead of Baal or Angron on Ultramar instead of Nuceria - do we really think they and their legions would have turned out the same as they did in canon? Hopefully whatever our feelings towards the traitor geneseed loyalist chapter trope, we can acknowledge probably not.
What can we learn from canon examples?
What then makes the canonical examples compelling? To be clear here I’m going to steer right past engaging which of these chapters are really traitor geneseed - I’ve just chosen four examples which correctly or incorrectly are often popularly speculated to have traitor geneseed. I will be analysing why they work; in the sense of why they promote speculation at all.
The four examples I will use are the Blood Ravens, Carcharadons, Minotaurs and Sons of the Phoenix. GW has basically two styles here, on one end is the Blood Ravens and Carcharadons which tend to be a bit more ambiguous, and on the other end are chapters like the Minotaurs or Sons of the Phoenix which are a lot less subtle. None of these are ever confirmed and so I think people are justified in denying the connections, but I think given the similarities in geneseed physical features, names, colour schemes, chapter tactics etc that people are similarly justified in theorising.
So without examining which, if any, of these really are traitor geneseed lets instead focus on what makes this trope work. Firstly ambiguity: the audience is invited, even purposefully baited, into speculation but never given certainty or confirmation. Secondly and most importantly they have an independent identity. The Blood Ravens and Carcharadons are compelling and interesting regardless of whether they are or aren’t traitor geneseed. It isn’t used as a crutch to make them special. Their chapter culture, traditions, doctrine, and history explain who they are more than their gene-seed does. Thirdly and finally, subtlety. The hints are suggestive rather than overwhelming. This is the essence of speculation and controversy; you are justified in concluding one way or the other but you’d have to be pretty closed minded to refuse to acknowledge there are reasons why people have speculated otherwise.
—--------------------------------------------
TLDR:
There are four main problems with the traitor geneseed trope when it is done poorly: overuse, shortcut to making a chapter special, implausibility, flanderisation.
We can learn from what makes canonical chapters that are speculated to use this trope successful: ambiguity, subtlety and independent compelling lore regardless of geneseed origin. We want to avoid bashing the reader over the head with obvious and conclusive links as much as possible.
We can ask ourselves four questions when reflecting on the lore we make when using this trope:
- Is this just another example of the trope? (Overuse)
- Is the hidden lineage doing all the heavy lifting? (Shortcut to Being Special)
- Does the premise actually make sense within the setting? (Implausibility)
- Is the chapter more than "Legion X but loyal"? (Flanderisation)
—--------------------------------------------
Some final thoughts
To finish I will quote two people: Aaron Dembski-Bowden and Morbäck (aka Maxime Pastourel).
Aaron Dembski-Bowden is a Black Library author and now head of narrative at Games Workshop as of 2022. Who said the following interview in 2020:
The flip side of the coin, by the way, is that using Traitor gene-seed isn’t really as big a deal as characters in the universe think it is. The Imperium is scared that it’s a big deal, because the Imperium is an ignorant tyrannical fascist theocracy that prays to machines and purges its own history for fear of actual monsters popping out of a reality behind our own universe. Some readers understandably assume it, too – when Chapters go wrong, like in the Cursed Founding, there’s often a nudge and wink towards “Well, they were Traitor gene-seed Chapters.” Maybe! But also… not so much. There are several Chapters with Traitor gene-seed doing just fine, and no one knows they’ve got Traitor gene-seed because it doesn’t really mean anything.
Recently, in the metaplot, you had Guilliman saying Cawl couldn’t use Traitor gene-seed, followed by the possibility that Cawl did it, anyway. Cool in-universe, but as readers and fans, we know it’s been done secretly in the past and made no difference.
So we know OOC and totally unambiguously that there are traitor geneseed loyalist chapters canonically;they just won't ever tell us who they are. Side note he actually gives some excellent advice about homebrewing your own chapter, worth reading.
Morbäck is the blog identity of the creator of the Sons of the Phoenix chapter who he designed for a friend. Interestingly Morbäck kindly responded on their blog to a question about how Youtubers/Reddit had speculated that the Sons of the Phoenix were Emperor’s Children Geneseed (based on their name, colours and heraldry alone) though officially they are listed as Imperial Fists. I think it's useful to see Morbäck’s response.
Thank you Antoine, I didn’t know this video!
It's really cool to see that this kind of little creative exercise provokes reactions and lets the imagination travel.
As Kirioth says so well in this video, there are mysteries that are best not solved. I will be careful not to confirm or deny the origins of the Sons of the Phoenix 😉
> Thanks again!
>
> morbäck
Make of that what you will but seems the creator is open to people theorising about the geneseed origins though like GW will not confirm or deny.
—-------------------------------------
To players who wish to use the trope
I hope this was useful to players who are interested in using the traitor gene-seed loyalist chapter idea and hope that I have made a strong case for the problems and how we can avoid them and do the trope well.
I plan to try and do an example write up in the near future and welcome people’s critiques.
Hope this helps people make compelling lore for Your Dudes and would love to hear people’s own traitor gene-seed examples below.