Anatomy of a Space Marine.
Deep within the Himalazian mountains, the Emperor of Mankind built a secret laboratory, the cradle of the Primarchs. These superhuman generals were destined to command gene-forged armies, leading humanity back into the stars and uniting lost societies beneath the Imperium’s banner.
To achieve this, the Emperor needed warriors beyond compare. He had already shaped the Legio Custodes by hand, perfecting each strand of their DNA. But such painstaking work could never scale to the vast numbers required for the Astartes. Instead, he devised the gene-seed: organs capable of transforming ordinary adolescent males into transhuman soldiers, given time and the proper treatments.
The first recruits came from Terra’s noble houses and those who had stood with the Emperor during the Unification Wars. Only candidates with the right genetic resilience could survive the implants, and even then, they faced brutal physical and mental trials. Attrition was staggering, and as the Legions grew, each developed its own traditions of testing that pushed aspirants to the brink.
Those who endured were rewarded with the gradual gift of transformation. Organ by organ, phase by phase, they proved themselves worthy to join the ranks of the Emperor’s chosen.
Phase zero (for some legions).
Once an aspirant has proven himself worthy of the Space Wolves, he must face the Test of Morkai. Before any gene-seed implantation begins, the candidate drinks from the Cup of Wulfen, a vessel containing the volatile Canis Helix. The ritual takes its name from Wulfen, one of Leman Russ’s household warriors. Though he swore loyalty, jealousy and hatred festered in his heart. When the Emperor came to claim Russ, the household pledged themselves as Fenris’s first Space Wolves. Wulfen was the first to drink from the cup. The transformation was immediate: his body twisted into a monstrous fusion of wolf and man. He lunged at Russ, only to be strangled by the Primarch’s hand. From that moment, Russ decreed that any aspirant unworthy of the Canis Helix would suffer the same fate, becoming one of the cursed Wulfen. The Blood Angels practice a similar rite. Their aspirants drink from a chalice said to contain the blood of Sanguinius himself. This act awakens the gene-seed, but it is also believed to be the moment when the flaw of the Red Thirst first takes root.
Phase One - Secondary Heart.
The first organ to be implanted is the easiest and requires no other organs to be present to function. This Organ simply acts as a backup if the primary heart is damaged or destroyed, and it enables the marine to survive fights in low-oxygen environments. In battle or stressful situations, the Secondary kicks in to increase blood flow throughout the body, allowing more oxygen to be transported and helping them stay in the fight longer.
Phase Two - Ossmodula (Iron Heart).
The first hormone-related organ to be implanted is the Ossmodula; the hormones secreted need to be combined with changes to the marine's diet. The diet needs to be ceramic-based, and once present, the organ begins to cause all of the bones in the body to increase in size and strength. Within 2 years of implantation, the ribs fuse into a mass of interlocking plates that will withstand limited ballistic missile damage. The Ossmodula works in concert with the next phase organ to increase the size of the Marine.
Phase Three - Biscopea (Forge of Strength).
Implanted within the chest, this small spherical organ's primary use is hormonal in nature; it increases the muscle growth of the marine and supplies the hormonal basis for the later organs. Usually, this is implanted between the ages of 10 and 12.
Phase four - Haemastamen (Blood Maker).
Implanted into the main circulatory system, this is a tiny organ that increases the haemoglobin content and greatly increases its ability to carry oxygen. This causes the Astartes blood to be a brighter red than that of baseline humans. Can be implanted along with phases 2 and 3.
Phase five - Larraman's Organ (Healer)
A small liver-shaped organ, implanted in the chest cavity and directly connected to the circulatory system. This organ creates and controls the production of special 'Larraman cells' that get released into the bloodstream. Once the marine receives an injury, they automatically attach themselves to the white blood cells (Leukocytes) and get carried to the site of the wound. Upon contact with the air, they form a near-instant patch of scar tissue, sealing the wound, therefore greatly surpassing the abilities of platelets on a massive scale. Although this miracle organ can greatly increase the chance of survival in a marine, it is not a guarantee that they will survive the most extensive injuries they face. This ability can be overtaxed, and they can still die from intensive damage during combat.
Phase six - Catalepsean Node (the Unsleeping)
A pea-sized node is implanted into the back of the brain. This remarkable organ relates to the circadian rhythm of sleep and the debilitating effects of sleep deprivation on the body. For full control over this organ, hypnotherapy and training are required. When the marine becomes sleep deprived, the node cuts in and begins to power down sections of the brain sequentially to allow some form of rest without reducing combat ability. This cannot replace sleep completely, but with time, a marine can go up to two weeks without sleep and will need no more than four hours to be back to full ability and ready to start the process again. Some marines, with practice, can go into a meditative trance and go even longer.
Phase Seven - Preomnor (Neutraliser).
The pre-stomach, spliced into the digestive stomach above the original stomach, allows the marine to eat poisonous or even completely indigestible materials. But more incredibly, the Preomnor is capable of biochemically analysing anything ingested and neutralising most known biochemical or inorganic toxins. Some newly implanted marines like to make a habit of trying anything they can just to test this out. Any acids that are absorbed from material are automatically stored in the Betcher's Gland (a later implant).
Phase Eight - Omophagea (the Remembrancer).
This organ is the reason for several flaws developing within some legions and later chapters. This implant is located in the spinal cord, but is actually part of the brain. Four nerve bundles are implanted, making a connection between the spine and the stomach wall. When the marine eats something, they can 'read or absorb the genetic material, the Omophagea transmits this gained information to the brain as a flash of memories or experiences. This organ has led to some legions developing blood drinking or flesh-eating rituals and going as far as gaining an unnatural craving for it.
Phase Nine - Multi-Lung (Imbiber).
A third lung is implanted to allow them to breathe in low oxygen environments, or poisonous environments, or even to grant partial ability to breathe underwater. The multi-lung has been used in parts of lore to produce a sonic attack scream to deafen and to disorientate mortals by the Talos of Night Lords. Other examples have been when the Lung was used to hyper oxygenate their bodies to avoid dropping unconscious during a rough landing in a drop-pod underfire.
Phase Ten - Occulobe (Eye of Vengeance).
This implant sits at the base of the brain and provides hormonal and genetic stimuli. This implant also requires optic-therapy by the Apothecaries at a later date. The optic therapy involves adjustments to the growth patterns and the light-reception portion of the eye. The end result is that the marine's vision is far superior to that of baseline humans. In low-light conditions, they can see just as well as in daylight, and they can see details at ease when viewing someone from a long distance.
Phase Eleven - Lyman's Ear (the Sentinel)
This implant completely replaces the marine's original ear; it artificially grants a couple of enhancements. The Ear makes the Space Marine immune to dizziness and motion sickness; he is able filter out and enhance certain sounds. The improvements granted are so great that they can hear a human heartbeat from a kilometer away, but the auditory enhancements aren't so intense that it overwhelms the Marine.
Phase Twelve - Sus-an Membrane (the Hibernator).
Initially implanted above the brain, this membrane eventually covers the entire brain. Although this implant is ineffective without follow-up chemical therapy and training, once this has been undertaken, it will allow a marine to survive even the worst of damages and end up in a state of suspended animation. This can slip into effect automatically during injuries in combat or by conscious choice. This can keep marines alive for years after the injuries have been received, and the correct chemical therapy or auto-suggestion can revive the marine from this state. The longest known in this period is Brother Silas Err of the Dark Angels legion, who got revived after 567 years.
Phase Thirteen - Melanchromic Organ (skinshield).
This organ is the reason for the gene-seed mutations in the Salamanders and occasional mutations in the Raven Guard and Blood Angels legions. This implant controls the amount of melanin in the skin. High levels of exposure to sunlight will result in the automatic darkening of the skin, which also grants the marine large amounts of protection from other types of radiation.
Phase fourteen - Oolitic Kidney (the Purifier).
This implant works in conjunction with the Secondary Heart implant; it allows the marine to quickly filter his total volume of blood, rendering him immune to even more poisons and toxins. This action does come with a high cost that can't be undertaken in combat, as it renders the marine unconscious. When this function isn't required, it operates in a passive capacity, monitoring the circulatory system and the function of all other organs.
Phase fifteen - Neuroglottis (the Devourer).
This implant enhances the marine's sense of taste to the point where it can identify many common chemicals by taste or smell on its own. A marine can use this implant to track a target, just by sampling the air. Mundane food tastes are enhanced just as much by this implant.
Phase sixteen - Mucranoid (the Weaver).
This implant allows the marine to sweat a substance that coats the skin to create a barrier against extreme heat or cold and offer limited protection in the void. Although to be put into effect, it needs to be activated by outside treatment, this is common when fighting in a void is expected.
Phase seventeen - Betcher's Gland (the Poison Bite).
This is two glands implanted into the lower lip alongside the salivary glands, another option is into the hard palate. This implant works similarly to a reptile's poison gland, working in conjunction with the earlier Preomnor implant, which synthesises and stores a corrosive acid that the marine is immune to. Within the lore, this has been used as a last-ditch attempt close combat weapon or to melt chains that held a marine captive.
Phase eighteen - Progenoids (Gene-seed).
The Progenoid Glands, known simply as the Gene-Seed, are the eighteenth and most vital of the Astartes’ implants. Each Space Marine carries two: one nestled in the neck, the other deep within the chest. These organs respond to the presence of the other gene-seed implants, generating germ cells through a process akin to cellular mitosis. Stored within the glands, these cells contain the genetic blueprint of the Primarch, not the Marine himself, and can be cultured into the nineteen organs required to forge a new warrior. For the Adeptus Astartes, this is the only form of reproduction they will ever know. After five years, the neck gland matures and may be harvested; the chest gland requires a full decade. Apothecaries recover them most often after death, using the Narthecium’s Reductor to extract the glands from fallen brothers. In this way, the Legion replenishes its ranks, and the warrior achieves a form of immortality—living on through the gene-seed that will shape the next generation of Space Marines.
Phase nineteen- Black Carapace (the Interface).
The Black Carapace is the final, and most vital, of the nineteen gene-seed implants bestowed upon a Space Marine neophyte. This neuroactive, fibrous layer is grafted beneath the skin of the torso, where an Apothecary carves interface points that will later bind the warrior’s nervous system to his Power Armour. Within hours, the Carapace hardens, and invasive synthetic fibers grow inward, entwining with the Marine’s neurons to create a living circuit between man and machine. This is a critical implant to interact with the power armour of the marine, even though Sisters of Battle and Inquisitors also use a type of power armour, their armour is slow and clumsy compared to the near speed of thought seamless actions the marine can undertake. Most legions only allow this implantation to go forward after a rite of passage has been completed or a term of service within the scout squads. Most legions do not consider Neophytes as battle brothers until the Carapace has been implanted and the Neophyte is ready for his armour.
