Genestealer Cult

The 2nd edition pic that has defined the identity of Genestealer Cults for decades.

"Praise be! The star children deliver us!"

– White Dwarf October 2016

"So prepare for the coup of the century!
Be prepared for the murkiest scam!
Meticulous planning, tenacity spanning,
Decades of denial, is simply why I’ll,
Be king undisputed! Respected! Saluted!
And seen for the wonder I am!
Yes my teeth and ambitions are bared!
Be prepared!"

– ”Be Prepared”, a mandatory song for all aspiring usurpers

"Dere's sumfink a bit weird about dis ere humie... Hang on a minute. One, two... er, three, er... wait! Three?! That's not right. He's got too many arms!"

– Ork Gargaz figuring out that something isn't right faster than the Imperium ever has.

The Genestealer Cults are a playable faction in Warhammer 40,000. Genestealer Cults are formed when a Genestealer has infiltrated a planet populated by sentient humanoid species and begins a family of infected individuals. These Cults have spread across the stars and predate the arrival of the hive fleets.

Overview

"In the name of the Star Children we are charged with conquering worlds. We must overthrow the oppressive regimes of the Imperium. We must crush the vile alien invaders and the worshippers of false gods who seek to steal our prizes from us. All this we must do through our own strength, guile and determination. In such an endeavour, there is no room for weakness or failure."

– Magus Rheng of the Cult of the Fanged Deliverer

The Genestealers (and their Cults) have undergone several major revisions, but in current fluff they are Tyranids that were sent ahead of the hive fleets to prepare worlds for the invasion of a hive fleet. Their long tongues contain a barbed ovipositor; when they encounter sentient anthropoid, they use this ovipositor to inject a "seed" into the host's body, combining the host species' genome with the greater Tyranid genome (hence the name Gene-stealer.) This is a method called the "Genestealer's Kiss," which is either a face-biting parody of a kiss or an injection under the ribcage. Fun fact, this biological process exists in real life under the name of "horizontal gene transfer", and is mostly used by bacteria to help other bacteria develop resistances to antibiotics, and more importantly is the main process involved in genetic engineering! More recently, the Genestealer Cult of the Twisted Helix has discovered how to extract this "seed" for use in contaminating food and medicine, allowing the Genestealer curse to spread to locations far removed from any actual Genestealer.

Regardless of the vector, the seed greatly alters the host's body on both physical and psychological levels over the course of a few hours, causing them to forget all about the infection and become subservient to the Purestrain's brood. The host is also driven to have children, even if they didn't want any before becoming infected; their partner does not have to be likewise infected, but it doesn't hurt. After a pregnant host (or whoever they impregnated) gives birth, their viciously malformed offspring creates a hive mind connection between itself, its parents, and the Genestealers (though this raises the question of how anyone else in the room during the birth, such as midwives, would react.) This connection and the mutations brought on by the Genestealer's seed proceed to subliminally twist the minds of both parents so that they unconditionally love their child and revere the Genestealers either as gods or as creatures sent by gods (the exact interpretation varies, you understand), usually fleeing into darkened tunnels, catacombs or sewers to avoid discovery. It is not even uncommon for Genestealer Cults to present, at least outwardly, as Emperor-worshipers, although inevitably they have some funky iconography like the whole four arms thing. Some of them, at least the rank and file, may even believe they're worshiping the Emperor instead of spacebugs. And, when not doing dastardly Genestealer things, they may really be about the overall work of the Imperium on a day-to-day basis, which is of course part and parcel with their infiltrationist aspects.

Eventually these infected individuals and their growing brood of offspring will come together with kindred spirits (that is, other Genestealer hybrids and their infected parents) to form a community/family dedicated to the Genestealers in both body and soul. As the family grows, they will continue to isolate themselves, eventually forming a Genestealer Cult. What follows is an ongoing process of hybrids breeding with captured and infected humans, with their human parents kept around both as breeding stock and for nursing and child-rearing. The second generation hybrids aren't as ugly as their parents, appearing more "normal"-looking but still obviously alien. However, that becomes a moot point once the third and fourth generation roll around, the fourth actually being virtually indistinguishable from actual full-members of their parent species; when they have kids they actually pop out purestrains, though these may have inherited a trait or two of the host species. The uglier members and Purestrain Genestealers typically lurk in the shadows far away from civilisation, while the intelligent and "human" members infiltrate and spy in almost every sector of society. Their psychic network lets them communicate with one another, even though some of the less-human hybrids (and the Purestrains) are incapable of speech, and when the brood mind becomes powerful enough, it will act as a beacon to Tyranid Hive Fleets. These fleets travel at various different speeds according to various different authors although generally always slower than Imperial warp drives, which means it is impractical for them to travel blindly, so they home in on the signal created by a large Genestealer Cult. When their arrival is imminent, they will directly contact the Cult, which will then engage in a full rebellion, sabotaging their planet's defenses in preparation for the fleet. This scenario is usually a win-win for the Tyranids, as even if the insurrection is crushed, they still probably went down swinging and cost the defenders valuable manpower and resources they needed to fight what's coming.

The exact manner in which a Cult reacts to the arrival of the Tyranids varies. According to the backstory for Hive Fleet Kraken, a planet called Larnarno was infiltrated by a Cult calling themselves the Celebrants of Nihilism. When the Tyranids showed up to consume the planet, 75% of the population calmly marched towards and aboard the bio-ships where they gladly accepted being brought to the digestion pits. However, a Cult generally has no idea what is about to happen to them, fully believing that the Tyranids are wonderful, enlightened beings and when they show up they'll all become one big happy space family. And for a bit, the Hive Mind actually leads them on and doesn't target the cult. For a brief moment the cultists get to live their dream of fighting alongside their beloved star gods, but as soon as the planet's defenses are basically done for, they are on the menu just like everybody else. Even worse, the Hive Mind overrides the independence of the Patriarch and Purestrains, at which point the glamour surrounding the Tyranid horrors fades, the cultists get a good look at what their angels really look like and they have just enough time to fail their SAN checks and scream. Any cultists that try to flee are consumed by the very father they worshiped and the very children they raised.

Some may ask, why would GW do this? Does GW hate the idea that anyone who is not of an Imperial faction might be allowed to have a happy ending? If you have to ask these questions, you probably don't understand the situation. The Genestealer Cults are literally nothing more than convenient tools that the Tyranids use to prepare worlds for consumption. Their sole purpose is to be nothing more than the A1 Steak Sauce that makes a meal go down easier for the hive fleets. The very genetic fabric of each Cult member, right down to the most lowly cultist, has been hijacked to achieve this end. If they fail, they will be destroyed by the civilizations they are attempting to infiltrate. If they succeed, they will be assimilated by the Hive Mind. Therefore for the Genestealer Cults, one way or the other, there can be no happy ending.

Way back in the days of Rogue Trader, Genestealer Cults also used to be able to be devoted to Chaos. That disappeared from the tabletop along with the old incarnation of the army, but in the fluff, this can apparently still happen, in certain very rare circumstances. One account describes a truly hilarious case of turnabout when a Cult's ship is sucked into a Warp storm and dumped on the edges of Nurgle's Garden, where the Genestealers and their minions get taught a thing or two about real corruption and parasitism by the Chaos God who wrote the book on it. Nurgle does eventually let the Cult go, because he's a nice guy, after he's thoroughly had his way with them of course, and they come back into realspace as basically a Plaguestealer Cult. What might've happened if the Cult had fallen into Slaanesh's domain, officially, we'll never know, because family-friendly GW doesn't have the balls to go there. Unofficially, we can make a pretty good guess. As a contrariwise example, there's a genestealer cult in a Inquisitor Czevak story who, marooned on a daemon world in the Eye after their space hulk was unfortunate enough to crash there, nonetheless hate and resist chaos and maintain a lot of Imperial iconography and so on (although they do consort with xenos and mutants, which, while heretical, is probably still well above par for the course given their living situation).

Interestingly, it appears that the rare Genestealer Cults that fall to Chaos worship may become decidedly unappetizing to the Tyranids, to the point where a hive fleet will ignore the cult's call and merrily skip past them to go chow down on some forest-moon instead of the world the cult had been desperately calling them towards. This ends up pushing a cult even further into Chaos worship, unaware that they are not in fact following the Hivemind but instead possibly a demented purple whore or a bloated pus-covered maggot man.

Genestealer Hybrids

The first Genestealer to infect a host (or hosts) grows larger and more intelligent with each mind added to the cult/family/whatever, eventually far surpassing its kin in strength, size and cunning, even becoming a powerful psyker. This Genestealer is known as the Patriarch, and acts as both the Cult's leader and the object of its devotion. The Patriarch's psychic connection to the Hive Mind allows it to maintain iron control over his brood as well as other lesser Tyranid organisms.

After the Purestrain infects a host, the infected human will reproduce with another human to produce the first generation of hybrids. Genestealer Cults will end up with members with various levels of Genestealer ancestry. In general, Genestealer Hybrids will breed with their non-Genestealer parent species causing their descendants to increasingly resemble that species, until the fourth generation of hybrids, whose children will be Purestrain Genestealers capable of "founding" new Genestealer Cults.

The Rogue Trader-era Genestealers also get a special mention, in the form of "Ymgarl Genestealers," a strain that supposedly comes from a population of Genestealers that got isolated on the moons of Ymgarl. They have tentacled, lamprey-like mouths and the ability to partially transform themselves depending on the circumstances, at the cost of being genetically unstable and only being able to feed on blood. In fact, they're so unstable that the Hive Mind deliberately abandoned them for fear that they would contaminate the Tyranid gene pool. Because of this, they compulsively seek to reach planets that have recently been visited by the Tyranids in a futile attempt to be reabsorbed into the Hive Fleets. If they weren't horrible monstrosities, their predicament would almost be sad. However, at some point between 5th and 6th Edition, the Ymgarl Genestealers lucked out and got absorbed into a Hive Fleet by some very desperate/caring Norn Queen. The result of this is that 6E Tyranids now have a Bio-Artefact (If you feel unclean about the name, that's natural) called the Ymgarl Factor that gives any Tyranid unit the same unstable properties rule, but now lack the assaulting from Outflanking.

Non-human Hybrids

As a final note, Warhammer 40,000 fiction is very human-centric, and so most Genestealer infestations depicted have occurred among human populations, but the Ciaphas Cain novels have suggested that Tau and Orks are also susceptible to Genestealer infection. The novel Death of Integrity also confirms that Genestealers will attack and assimilate other xenos, though this plot point lasts about one paragraph. What, exactly, a Tau Genestealer Hybrid would look like is the subject of much speculation. The short story The Greater Evil depicts one, and the answer is: Horrifying, and obviously blue. As shown in the later short story The Voice of Experience, the Tau are also well-aware of Genestealers by this point and the threat they pose. There is old canon art of Ork Genestealer hybrids, but given the vast amount of retcons since then its canon status is questionable...

Orks

ORKY NIDS!!!!!!!!!!!

It should be noted that Orks reproduce asexually by way of fungal spores they secrete both at a perpetual slow trickle from their skin while alive and en masse while a decaying corpse (and also that "Ork" is but one of many many different Orkoid phenotypes that a given spore might develop into depending on environmental conditions, so one has to wonder how the genestealer mutations might interact with a spore that grew into, say, a mushroom), so it's pretty hard to envision an Orkified Genestealer Cult actually working, or lasting beyond the first generation or two, since they have no ways of mixing genes to produce purestrains in time. Even if they could, the Orks have an inherent ability to determine if one of their own isn't proppa Orky and will inevitably krump the gits. Some old, old fluff portrayed Purestrain genestealers descended from Ork hybrids as having denser musculature (and most likely greater physical strength). In another of these dusty accounts, an incident on the fringe of the Octarius system had a massive, purple, six-limbed Gargant attacking a Guard regiment. When it was melta'd open, purestrain genestealers emerged to eat the Guardsmen. You are encouraged to take these older bits of fluff with a generous pinch of salt. In any event, ancient and likely non-canonical fluff aside, the unique quirks of Ork biology boil down to the fact any attempt to infest an Ork warband would almost certainly fail and not be worth the effort in the first place. Commissar Cain encountered a genestealer infested space hulk in which genestealers were using infested orks to guard their hibernation chambers.

As of 2021, GeeDubs has recently reaffirmed their existence in a White Dwarf. According to the article, they generally show up in Ork Kommandos, as they tend to live away from the main force of Orks, making it easier to slip in. Also in the article, they showed you how to make your own out of Acolyte Hybrids, Abberants, and the new Kommandos. That's right, GW is encouraging you to kitbash. Did we slip into an alternate dimension?

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  Imagine encountering one of these during the Octarius War.

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Tau

Tau, similarly, have certain complications which may prevent Genestealer infestation. Firstly, their Kroot allies can tell if a person is infected or not simply by tasting some of their blood, and secondly, Tau-tech is certainly advanced enough to scan for this threat once they know about it. Furthermore, Tau explicitly practice caste-restricted bureaucratically arranged breeding processes; Tau don't have kids until their higher ups decide they should, and they don't even get to pick their own partners. Two Tau get paired up by the decision of a committee, spend a couple of days off work having sex, then separate and go their separate ways. This means the genestealer taint is seriously difficult to spread amongst the race. The caste-based structure of Tau society also poses problems to any potential Tauified Genestealers, and that's without presuming the caste-system is now so inherent that different castes can't even physically breed with each other anymore. However, fluff states that BREEDING is controlled, and doesn't touch on recreational sex. If such is unrestricted in Tau society, then it would simply be a matter of overcoming the probably enforced contraceptive measures.

Tau Genestealers are confirmed in the novel Deathwatch: Shadowbreaker as they're being deliberately engineered by a rogue Inquisitor to use a planet contested by the Tau and Imperium as a bioweapon delivery system. The narration makes it clear that the Tau are doing it without the permission of the Ethereals and that the Inquisitor is conning the Tau commander into letting it happen. However, all the Taustealers get blown up (It is a novel about the Deathwatch, after all) so they don't get a chance to spread beyond the planet. On top of all of that, according to the new Genestealer Cults Codex, not only can Tau-Genestealer hybrids happen, but one time they were deliberately created by a team of Earth Caste researchers who wanted to see what would happen. The infection got out of control and actually ended in violence. It's even implied that they may have produced a hybrid Ethereal, which would be a disaster for the Tau given how obedience to the Ethereal caste is basically hard coded into their DNA.

Eldar

While it is possible for Genestealers to infect the Eldar, it's extremely hard for them to get anywhere with any of the four varieties due to their highly advanced medical technology (all four, yes even the Exodites), universal empathic abilities, very regimented lifestyles (Craftworld), slow breeding rate and the fact that irregular psychic activity amongst them gets located and dealt with very quickly (all four, heck mind bulletry is pretty much the only thing the Dark Eldar ban). Even when they are infected, the taint spreads much more slowly due to the Eldar's prolonged gestation period, which makes infecting them more trouble than it is worth in most situations.

So far the only examples among Eldar are those who knowingly and openly embraced their pants-thieving overlords. In the novel "Ghost Warrior", we have Genestealer Eldar on a lost Craftworld named Zaisuthra. Needless to say, the other Ynnari who contacted them were pissed. This was done in their misguided attempt to avoid getting consumed by Slaanesh because this Craftworld had left before the Infinity Circuit was invented and thus didn't have one; their logic was that if they gave themselves over to the Broodmind, their souls would be assimilated before Slaanesh could consume them. There is also something of a Genestealer cult growing among the Dark Eldar in Commorragh. After a raid with lots of captives taken to Commorragh, the Haemonculi found out some of them were Genestealer cultists. The hybrids were singled out and experimented on so their mutations would emerge. When some bored Dark Eldar among the social elite found out about this, they paid the Haemonculi to graft these Genestealer body parts on them for kicks (given how Genestealer reproduction involve a genetic re-write of infected hosts using the Stealer's own DNA, you can see what a stupid idea this is). It looks like the Hive Mind might find a way into Commorragh given how these Dark Eldar, who collectively call themselves the Vorgani, started forming tight-knit groups and share a singular obsession over a Tyranid-infested planet trapped in the Webway.

And of course, the haemonculi know this and think this is just a jolly and amusing thing because of course the sickest fucks in all the galaxy would look at this and think, "what an interesting turn of events!".

Others

Fanart of Genestealer Hybrids of most WH40K races, along with some other Xenos from Popular Culture

If a Genestealer Cult somehow got somewhere near a Stryxis convoy and for some reason decided they wanted to interbreed with them they would quickly run into two main problems; the first being that Stryxis are extremely untrustworthy little shits so they don't exactly operate in large enough groups to be really worth the effort, the second problem also being that the Stryxis are untrustworthy little shits and would probably scam the Genestealer Cult of all its possessions before enslaving the bastards (assuming they don't "trade" a few hundred bullets in exchange for the Tyranids teeth to sell to some Orks or something).

The Q'Orl probably already know about this shit considering their size but since they do the whole queen thing it would be VERY hard for a genestealer infection to take place. Considering they're bugs too might play a part considering even a Ork is way more physically similar to a human or Eldar then what is essentially a giant cockroach/wasp hybrid. As for Ambulls their rapid regeneration and reliance on parasites might even HEAL the infection for all we Know!

As for the Necrons, they're goddamn undead robots. If you even consider this possibility you're the biggest idiot since Magnus the Red.

In earlier editions, Ymgarl Genestealers were said to be hybrids with a native, leechlike sapient race to Ymgarl, the Csith. The Salamanders wiped out the Csith, but were unable to wipe out the Ymgarl Genestealers.

Finally, and perhaps most troubling, is the mention that Tyranids have been targeting Hrud warrens. Hrud lack the defenses of the above races and are naturally predisposed towards infesting a planet and migrating en mass to a new one. The Genestealer hybrids, likewise, gain enhanced stealth and reaction speed (such as those 5++ saves the 'stealers now enjoy.)

Tabletop (40k Army, 7th Edition and up)

Uh? What do you mean Inquisitors don't have an additional set of wing-claws?

A very small range of really terrible looking Genestealer Cult minis were produced during 1st/2nd Edition, and the legendary 2nd Edition Tyranid Codex also featured a Cult army list. However, the vast updates wrought by 3rd Edition in 1998 basically eliminated Genestealer Cults as a playable force. As a result, while the Genestealer Cults were a frequent mention in the lore they were completely absent from the tabletop for nearly two decades (aside from the Genestealers themselves, of course).

This all changed in 2016. First, Deathwatch: Overkill started us out with rules and models for cultists, in this case various hybrids wielding mining equipment led by a Genestealer patriarch, with hybrid preachers and enforcers. Finally, near the end of 7th Edition, long-suffering Genestealer Cult fans (yes, all three of them!) were finally rewarded with a beautiful new range of minis and a brand new Codex, chock full of disturbing and characterful units. And there was much rejoicing.

Cults get a super-genestealer called a Patriarch, the progenitor of the cult, as the main HQ choice. There's also the Magus, acting as the cult's psyker, and the Primus, their version of a general/champion. You also get regular genestealers, though they're actually much better than Tyranid genestealers as they're hardier and stealthier. The troops themselves are roughly similar to Chaos Cultists, with Neophyte Hybrids being armed with guns and improvised equipment, while Acolyte Hybrids are better in close combat. The Cult can also steal Guard vehicles, namely the Leman Russ Battle Tank, Chimera, and Sentinel, as well as their version of a Technical called the Goliath Truck. You can also just straight up steal Guardsmen and field them as Neophyte Hybrids. All cult members specialize in ambushing opponents, and get major bonuses from their leaders. In addition, cult leaders benefit from the Unquestioning Loyalty rule, meaning so long as you have enough meatshields nearby you can keep them alive. Furthermore, Acolytes, Neophytes, and Brood Brothers are all dirt cheap, and can easily be taken in large numbers rivalling the IG and Orks.

Genestealer Cults are able to ally with Tyranid detachments (though, as mentioned before, they're not Battle Brothers as the Tyranids view their cultists as dessert rather than the main course). Curiously, they can also ally with Guardsmen, as a way to represent the fact that they will infiltrate Guardsman/PDF forces prior to the invasion, so if you feel so inclined, you can augment your forces with even more Guard vehicles.

See Also

• Tactics on how to play them.
• Genestealer Cult Creation Tables - why not generate your own Cult?
• Jeanstealer - One of /tg/'s creations. A rather confused Tyranid genestealer that is only driven to steal denim trousers.
• Genestealer Cult Rules 40k Rules for the new Genestealer Cult from Deathwatch: Overkill