40K Lore: To Build a Space Marine

The Imperium will have it’s work cut out for it if they want to improve on the Adeptus Astartes.

To Build a Space Marine

It takes a considerable deal of time to transform a normal human into a Space Marine. They receive implants known as gene-seed which transform their bodies and give them superhuman abilities – making them capable of spitting acidic venom, absorbing the memories of the dead by eating their flesh, darkening their skin to protect it from radiation, and operating for long periods without sleep by switching off parts of their brains at a time.


Recruits are chosen from the best warriors among humanity. Naturally this makes Death and Feral Worlds prized recruitment grounds, as such harsh and primal conditions produce the best warriors. However hive worlds are considered the ideal source of potential recruits, the populace of the lower levels composed of some of the most murderous scum in the human Imperium. Whole gangs of hive scum are sometimes hunted down and captured for recruitment. Among the most valued traits in a recruit are aggression and psychotic-level killer instinct. More rarely, certain Civilized Worlds are also recruited from.


Recruits must be fairly young, because implants often do not become fully functional if the recipient has reached a certain level of physical maturity. They must be male because the zygotes are keyed to male hormones and tissue types. Only a small percentage of people are compatible to receive the implants and hypno-suggestion to turn them into Marines. Before the process of implantation begins the potential recruit receives tissue compatibility tests and psychological screening. If the testing proves successful the recruit becomes a neophyte. After the organ implantation process he becomes an initiate.

Even once the organs are implanted they are generally inactive or useless without associated training and hypnotherapy and chemical treatment. Most recruits join the ranks as a brother between the age of 16-18 years.

Astartes Implants

The 19 implanted organs are very complicated, and because several of them only work properly or at all in the presence of other implants, the removal, mutation or failure of one organ can affect the precise functioning of the others. Because of this, and the fact that each Chapter’s gene-seed belongs to that Chapter alone, different Chapters display different characteristics and use different sets of implants and methods of implantation.

Throughout the implantation process the Marine must undergo various forms of conditioning in order for the implanted organs to develop and become part of his physiology.

Listed below is the complete set of implants used:

  • Phases 1-3 can be introduced at the same time, ideally between 10 and 14 years of age.
  • Phases 4 and 5 can be introduced at the same time, ideally between 12 and 14 years of age.
  • Hypnotherapy normally begins at phase 6, ideally sometime between 14 and 17 years of age.
  • Phases 7 to 9 are normally introduced simultaneously, ideally at a point between 14 and 16 years old. The following series of organs are also ideally implanted between the ages of 14 and 16.
  • Phases 14 and 15 may be introduced at the same time, ideally between 15 and 16 years of age. The remaining series of implants are then ideally introduced to the recipient between the ages of 16 and 18.

Secondary Heart

Phase 1: This simplest and most self-sufficient of implants allows a Space Marine to survive his other heart being damaged or destroyed, and to survive in low oxygen environments. Not just a back-up, the secondary heart can boost the blood-flow around the Marine’s body.


Phase 2: A small, complex, tubular organ, the ossmodula secretes hormones that both affect the ossification of the skeleton and encourages the forming bone growths to absorb ceramic-based chemicals that are laced into the Marine’s diet. This drastically alters the way a Space Marine’s bones grow and develop. Two years after this implant is first put in the subject’s long bones will have increased in size and strength (along with most other bones), and the rib cage will have been fused into a solid mass of bulletproof, interlocking plates.


Phase 3: This small, circular organ is inserted into the chest cavity and releases hormones that vastly increase muscle growth throughout the marine’s body. It also serves to form the hormonal basis for many of the later implants.


Phase 4: Implanted into the main circulatory system, this tiny implant not only increases the haemoglobin content of the subject’s blood, making it more efficient at carrying oxygen around the body and making the subject’s blood a bright red, it also serves to monitor and control the actions of the phase 2 and phase 3 implants.

Larraman’s Organ

Phase 5: A liver-shaped organ about the size of a golf-ball, this implant is placed within the chest cavity and connected to the circulatory system. It generates and controls ‘Larraman cells’ which are released into the blood stream if the recipient is wounded. They attach themselves to leucocytes in the blood and are carried to the site of the wound, where upon contact with air they form a near instant patch of scar tissue, sealing any wounds the Space Marine may suffer.

Catalepsean Node

Phase 6: Implanted into the back of the brain, this pea-sized organ influences the circadian rhythms of sleep and the body’s response to sleep deprivation. If deprived of sleep, the catalepsean node cuts in. The node allows a Marine to sleep and remain awake at the same time by switching off areas of his brain sequentially. This process cannot replace sleep entirely, but increases the Marines survivability by allowing perception of the environment while resting. This means that a Space Marine needs no more than 4 hours of sleep a day, and can potentially go for 2 weeks without any sleep at all.


Phase 7: This is essentially a pre-stomach that can neutralise otherwise poisonous or indigestible foods. No actual digestion takes place in the preomnor, as it acts as a decontamination chamber placed before the natural stomach in the body’s system and can be isolated from the rest of the digestive tract in order to contain particularly troublesome intake.


Phase 8: This implant, also called “the Remembrancer”, allows a Space Marine to ‘learn by eating’. It is situated in the spinal cord but is actually part of the brain. Four nerve bundles are implanted connecting the spine and the stomach wall. Able to ‘read’ or absorb genetic material consumed by the marine, the omophagea transmits the gained information to the Marine’s brain as a set of memories or experiences. It is the presence of this organ which has led to the various flesh-eating and blood-drinking rituals for which the Astartes are famous, as well as giving names to chapters such as the Blood Drinkers and Flesh Tearers. Over time, mutations in this implant have given some chapters unnatural craving for blood or flesh.


Phase 9: This additional lung activates when a Space Marine needs to breathe in low-oxygen or poisoned atmospheres, and even water. The natural lungs are closed off by a sphincter muscle associated with the multi-lung and the implanted organ takes over breathing operations. It has highly efficient toxin dispersal systems.


Phase 10: This implant sits at the base of the brain, and provides hormonal and genetic stimuli which enable a Marine’s eyes to respond to optic-therapy. This in turn allows the Apothecaries to make adjustments to the growth patterns of the eye and the light-receptive retinal cells – the result being that Space Marines have far superior vision to normal humans, and can see in low-light conditions almost as well as in daylight.

Lyman’s Ear

Phase 11: Not only does this implant make a Space Marine immune from dizziness or motion sickness but also allows Space Marines to consciously filter out and enhance certain sounds. The Lyman’s Ear completely replaces a Marine’s original ear. It is externally indistinguishable from a normal human ear.

Sus-an Membrane

Phase 12: Initially implanted above the brain, this membrane eventually merges with the recipient’s entire brain. Ineffective without follow-up chemical therapy and training, but with sufficient training a Space Marine can use this implant to enter a state of suspended animation, consciously or as an automatic reaction to extreme trauma, keeping the Marine alive for years, even if he has suffered otherwise mortal wounds. Only the appropriate chemical therapy or auto-suggestion can revive a Marine from this state. The longest recorded period spent in suspended animation was undertaken by Brother Silas Err of the Dark Angels, who was revived after 567 years.

Melanchromic Organ

Phase 13: This implant controls the amount of melanin in a Marine’s skin. Exposure to high levels of sunlight will result in the Marine’s skin darkening to compensate. It also protects the Marine from other forms of radiation.

Oolitic Kidney

Phase 14: In conjunction with the secondary heart this implant allows a Space Marine to filter his blood very quickly, rendering him immune to most poisons. This action comes at a price, however, as this emergency detoxification usually renders the Marine unconscious while his blood is circulated at high speed. The organ’s everyday function is to monitor the entire circulatory system and allow other organs to function effectively.


Phase 15: This enhances a Space Marine’s sense of taste to such a high degree that he can identify many common chemicals by taste alone. A Marine can even track down his target by taste.


Phase 16: This implant allows a Space Marine to sweat a substance that coats the skin and offers resistance to extreme heat and cold and can even provide some protection for the marine in a vacuum. This can only be activated by outside treatment, and is common when Space Marines are expected to be fighting in vacuum.

Betcher’s Gland

Phase 17: Consists of two identical glands, implanted either into the lower lip, alongside the salivary glands or into the hard palette. The gland works in a similar way to the poison gland of venomous reptiles by synthesizing and storing deadly poison, which the Marines themselves are immune to due to the gland’s presence. This allows a Space Marine to spit a blinding contact poison. The poison is also corrosive and can even burn away strong metals given sufficient time.


Phase 18: There are two of these glands, one situated in the neck and the other within the chest cavity. These glands are vitally important and represent the future of the Chapter, as the only way new gene-seed can be produced is by reproducing it within the bodies of the Marines themselves. This is the implant’s only purpose. The glands absorb genetic material from the other implanted organs. When they have matured each gland will have developed a single gene-seed corresponding to each of the zygotes which have been implanted into the Marine.

These take time (5 years in the first case, 10 in the latter) to mature into gene-seed. The gene-seed can then be extracted and used to create more Space Marines.

Black Carapace

Phase 19: The most distinctive implant, it resembles a film of black plastic that is implanted directly beneath the skin of the Marine’s torso in sheets. It hardens on the outside and sends invasive neural bundles into the Marine’s body. After the organ has matured the recipient is then fitted with neural sensors and interface points cut into the carapace’s surface. This allows a Space Marine to interface directly with his Power Armour. Without the Black Carapace many of the systems of the power armour will not function. While driving the vehicles of the Chapter, special spinal interface plugged into power armour and Black Carapace to provide the Space Marine an intuitive ‘feel’ for vehicles systems and controls, literally making him a part of his vehicle.

That’s just the physical organs – now onto the training and indoctrination…

Learn More of Space Marine Creation

~ We will see what the Adeptus Mechanicus has come up with to beat this… Many have tried, and many have failed.

  • Honest Kairos

    Phase 20: Increase Matt Ward dosage past recommended therapeutic levels.

  • benn grimm

    Yeah, no you don’t need to bother with all that any more, that’s from back in the old days when they tried to make it all sound fairly plausible, they’re using magic now; no need for explanation. Gullyman farts, Cawl bottles it; hey presto a new super duper marine is born…

    • Crevab

      Out of curiosity I looked up Cawl on Lexicanum…

      10,000 years old? GW just pulls an Arch Magos from the time of the Emperor out their butts? Please someone tell me he was in stasis the last 99 hundred years.

      I just…

      I was just thinking about one of the 3rd ed fluff pieces. While fighting Orks, a marine bemoaning the state that his chapter’s wargear was in.
      That aspect of 40k has been dying since 5th.

      Really, 10000 years? The hell’s he been doing?

      • PrimoFederalist

        I thought the same thing when I read Fall of Cadia. The dude would be venerated by the entire Imperium. Forget Bjorn, he’s in stasis most of the time. It’s like giving

        • dinodoc

          I’m kinda curious why he’s not Fabricator-General of Mars

      • Andrew

        “Really, 10000 years? The hell’s he been doing?”

        Working on new Space Marines and reviving RG, who has the authority to order new SMs without too many people screeching ‘HERESY!!!’.

      • palaeomerus

        He’s like an ax that is so well made that you replace the handle and the head whenever they wear out and then WHOOPS it’s 10,000 years old! Well how about that! At this point he’s software and a fossilized thumbnail.

    • Andrew

      I kind of feel like anyone arguing that these new marines don’t fit with the fluff, in a universe as ridiculously OTT as WH40k, might as well be arguing about what is the correct shade of pink for a unicorn.

      • Karru

        There are so many stupid plotholes with the new marines which makes them dumb. It also completely re-writes the entire canon of Space Marines and the Emperor’s design. If these new marines can be manufactured in vats, what stops Imperium from making a grand army that will just rofl stomp everything?

        • Agent of Change

          This is exactly the problem… If the Imperium could manage this even with sleeping beauty and “Deus Ex Mechanicum” how in the hell did they not manage to prevent the decay of technology.

          How exactly has humanity been on the ropes if this technology could just be whipped up seemingly overnight?

          • Karru

            Indeed. Space Marines were meant to be the defenders of humanity, warriors without equals. Why aren’t they doing that? Because making them is very hard. A new Space Marine isn’t made as quickly as a Guardsmen. This was a reasonable explanation why they weren’t able to do their job.

            Suddenly Imperium has their own vat grown army of soldiers stronger than those which the Emperor created. The one who created the primarchs is now being beaten by a Tech-priest. A tech-priest that decided to show up “after 10.000 years” magically at the time of their greatest need.

          • Steven Hyche

            It was the loss of the primarchs that made it so hard to make new marines in the first place. So when one returns that does change things.

          • Derek Lee

            Custodes and thunderwarriors are/where more powerful than Space Marines. The first two where created in well fortified labs and the space marines where designed to be openly recruited from worlds conquered by the Great Crusade. I took from the fluff I’ve read that space marines are the model-T of the super soldier world; “easy” to assemble and to mass produce(more than custodes), but easier to maintain than the Thunderwarriors.

          • Kyle

            Bureaucratic inertia? Which actually given how in the fluff the Imperium’s governing bodies are described is pretty believable. Now they got a new leader and a guy who had been prepping for thousands of years to get started on new stuff.

        • Andrew

          I’m sure that GW will find plenty of things to keep them busy; 4th War of Armageddon, a new Hive Fleet, that massive warp storm that’s cut the Galaxy in half, etc…

          • Karru

            If the Space Marines have been able to defend the galaxy well to this point, these new marines should be able to take the offensive and just stomp their way through the enemies of the Imperium.

            That’s the issue here. Imperium is no longer this massive empire which has been able to defend itself with the “limited” resources that is Space Marines. If there ever was a massive threat, Space Marines would stop it. Now they bring in soldiers that are better than Space Marines AND can be manufactured in vats. There is nothing that can threaten Imperium then.

          • Andrew

            Like I said, I’m sure GW will find some new threat to balance them out. You say there are so many stupid plot holes with the new marines, but 40k is mostly composed of plot holes; held together by strings of gothic sci-fi and deus ex machina moments. I think players start to forget this when they’ve been ‘living’ in the fluff long enough.

          • Steven Hyche

            The primarches were made in vats. That doesnt mean they were “mass produced”. You dont even know how many or what is involved in creating them. You saw one picture of vats and have forged your own narrative.

  • KnightShift

    Is it just me, or does the Remembrancer seem pretty hokey and outlandish even for 40K?

    • Severius_Tolluck

      It makes perfect sense. They must have taken it from “Sword of the Lictor” by Gene Wolfe. There is a creature that stalks prey by mimicking other victims family members it had previously eaten.
      But in the context of 40K it makes sense. Marines now do not need to take prisoners for interrogation. They just bash the heads in, eat the brain, and now they know where they are hiding or up to.

      • DUDE…super extra mega bonus points for knowing about Gene Wolfe. The Book of the New Sun was a FANTASTIC, complex, and sometimes disturbing series.

        • Severius_Tolluck

          Was my fave series as a Teen. It’s why my screen name in countless games was Terminus Est. The grim dark takes many elements from the series here and there. Also hence the Severius as a homage to Severian.

      • Nightwalker

        Except memories are based on synaptic connections, not genetic (or epi-genetic) modifications.

        Yes, there is some argument showing that “memories” or experiences can be passed down through genetic modifications, but these would appear in gamete cells if they were to be germline.

        Ergo, if you want this to be effective based on that hypothesis, the space marine would have to eat it’s victim’s balls, not brain

  • petrow84

    That’s how they do it. Man, if there would be a video, with the same quality, and fast-forwarding the making…


  • Nightwalker

    As someone who has studied biology and physics (PhD), this hurts me in ways I am not okay with