Space Marines codex cover

Space Marines of the Ultramarines Chapter

The Space Marines (known as Adeptus Astartes in High Gothic, and nicknamed the "Angels of Death") are genetically enhanced super-soldiers of the Imperium of Man, created by the Emperor of Man preceding the period known as the Great Crusade.

Space Marines are giants enhanced by genetic modification, biological and cybernetic implants, extensive medical and hypnotherapy, combined with inhuman amounts of training and experience. Leading lives of unending battle and able to live centuries without signs of aging, many veteran Space Marines have honed their skills in the art of war while fighting and purging the enemies of Man in dozens, or even hundreds, of war campaigns. Their implants allow the use of Space Marines' signature power armor, a heavily armored suit that augments their already incredible strength, and provides integrated survival/medical functions.


Originally composed of twenty Legions (of which the Ultramarines were one), following the Horus Heresy civil war and the defection of nine Legions to the Ruinous Powers of Chaos, each Legion was seperated into smaller Chapters to ensure that no single force of Space Marines could threaten the Imperium should they rebel. Currently, there are around one thousand Chapters founded at different times, about half of which are derived from the Ultramarines gene-seed.

The Primarch ProjectEdit


The Emperor with early Space Marines

The history of the Astartes reaches back to the earliest days of the Imperium of Man. It was the period known as the Age of Strife, in the 30th millennium; the galactic nation had fallen, outlying colonies lost, and Terra had regressed to an uncivilized battleground of bickering minor warlords. Then the Emperor of Man appeared, a messianic leader with clearly superhuman physique and psychic abilities. The Emperor employed genetically engineered elite infantry in key roles and quickly secured the entire homeworld under his command.

The Emperor was planning more: to retake the galactic empire. To achieve this, he had a secret plan known as the Primarch Project – he was creating 20 more superhuman generals to lead his armies. These generals would be the Primarchs, not quite clones but possessing some of the Emperor's genetic code and approaching his powers. However, the Emperor's secret base on Luna – the moon of Terra – was struck by a disaster. The infant Primarchs disappeared. Intervention of the Chaos Gods, and probably a Warp anomaly removing the children, was suspected, but the truth is not known.

The Great CrusadeEdit

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The Emperor during the Great Crusade

The Emperor could sense that the Primarchs were not destroyed but scattered, and revised his plan. Using the progress made in the creation of the Primarchs, twenty units of new, more advanced, genetically engineered super-soldiers were made, each unit based on the DNA of one Primarch. These units were the Space Marine Legions, much larger than the Chapters, with up to 10,000–15,000 Marines in a Legion.

With this new elite force – and the early Imperial Army – the Emperor set out to reclaim his lost Primarchs, of course retaking the human empire in the process. This 200-year expansion war became known as the Great Crusade. The first Primarch to be found was Horus, who took command of his Legion – the 16th – and named it the Luna Wolves. Horus grew close to his "father", becoming the Emperor's right hand and later the Warmaster of the entire Imperial military.

More Primarchs were found, fully grown and more often than not ruling the worlds they had been cast on in their infancy. All assumed their positions, some with fervor and some with reluctance. Along with Primarchs, the Legions received names: Dark Angels, Emperor's Children, Iron Warriors, White Scars, Space Wolves, Imperial Fists, Night Lords, Blood Angels, Iron Hands, World Eaters, Ultramarines, Death Guard, Thousand Sons, Word Bearers, Salamanders, Raven Guard, Alpha Legion. The fates of two Primarchs and Legions are unknown, all records destroyed, so it is not known whether they were found during the Crusade.

With the Legions now led by their Primarchs, the Imperium was unstoppable. They retook their previous territory and expanded beyond, claiming up to a million worlds. The Emperor became satisfied and left the command to Warmaster Horus. Some of the Primarchs felt that the Emperor had abandoned them.

The Horus HeresyEdit

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The Emperor confronts Horus over the body of Sanguinius

In the golden age of the Imperium, disaster struck again. Horus was severely wounded in battle and became close to dying. The desperate situation called for help from natives – later believed to be Chaos cultists – and during his weakness, the recovering Horus was apparently tainted by Chaos. He began to plan a rebellion and secretly converted other Primarchs to his cause.

Horus' betrayal culminated in a massive civil war known as the Horus Heresy. Nine of the Legiones Astartes turned traitor and almost overthrew the Imperium. Terra was sieged and loyalist Primarchs were killed, Legions decimated. On the verge of defeat, the Emperor and Sanguinius teleported aboard Horus' flagship and confronted him. Sanguinius was killed by Horus, who in turn was slain by the Emperor. However, the Emperor himself was mortally wounded and had to be placed on the Golden Throne, a life support system sustaining his withered husk in suspended animation.

The traitors, effectively decapitated, broke and retreated to the Eye of Terror. However, the Imperium was severely crippled and without its leader as well.


Emperor golden throne

The Emperor's corpse on the Golden Throne

Part of the Post-Heresy changes to the Imperium was the division and re-charter of the Space Marines Legions. Many of the old chapters were reformed and amalgamated into newer forces with completely different identities. The Codex Astartes had much to do with this reformation.

Creation processEdit

Space marine terminator procedure

Space Marine being fitted with Terminator armor

The creation of a Space Marine begins with selecting a suitable recruit. The subject must be male, possess tissue types compatible with the gene-seed, and be young enough (Index Astartes states that the implantation process must be started at age 10 to 14 and finished at age 16 to 18). He must be fearless, sufficiently aggressive and physically powerful. For this reason, primitive warrior cultures may be used for recruitment. Additionally, the phase 6, 10 and 12 implants require the subject to be susceptible to hypnotherapy. Potential recruits are called "aspirants" and must usually face challenges such as fighting tournaments and other screening.

When the aspirant is deemed to have a chance of surviving the process, he is termed a "neophyte" and subjected to heavy bio-cybernetic implantation that consists of 19 stages.

  1. Secondary heart: The Marine is implanted with a second heart to improve his performance and keep him going in spite of catastrophic injuries.
  2. Ossmodula: An endocrine gland causing the skeleton to grow larger and harden considerably. Makes them inhumanly tall, at about 2.7 m, and fuses the rib cage into a solid plate.
  3. Biscopea: An endocrine gland stimulating muscle growth. Makes them even bigger
  4. Haemastamen: An intravascular implant that controls the phase 2–3 implants and improves the Marine's blood, making it more efficient at carrying oxygen to the organs. Allows the Astartes to operate in low-oxygen atmospheres; also changes their blood color to a lighter shade of red.
  5. Larraman's organ: Generates and stores Larraman cells, which instantly form scar tissue when coming in contact with air, quickly closing wounds.
  6. Catalepsean node: Brain implant allowing the Marine to "switch off" limited areas of the brain sequentially, prolonging the time he can go without proper sleep. Record stands at 328 hours.
  7. Preomnor: Pre-digestive stomach allowing the Marine to eat many poisonous or inedible things.
  8. Omophagea: An organ that absorbs genetic material from animal tissues, enabling the Marine to gain memories from creatures he eats.
  9. Multi-lung: A third lung that works more efficiently than the original ones and tolerates toxic atmospheres. A sphincter can stop normal breathing while this is used.
  10. Occulobe: Hormonal implant making certain eye enhancement procedures possible. Indirectly results in improved visual acuity and a degree of night vision.
  11. Lyman's ear: The ears are modified so that the Marine can consciously enhance or filter sounds and becomes immune to inner ear symptoms (vertigo, nausea, etc.)
  12. Sus-an membrane: A brain implant that requires medication and training to function. Allows the Marine to enter a state of suspended animation, surviving even if wounded mortally.
  13. Melanochrome: An implant mainly controlling pigmentation of the skin, providing protection from ultraviolet light, but offers limited protection against other radiation types as well.
  14. Oolitic kidney: A kidney-like implant providing improved blood filtration and detoxification, increasing the Marine's tolerance to poisons and toxins. Also improves the functionality of other implants.
  15. Neuroglottis: A mouth cavity implant that allows assessing the composition (possible poisons, etc.) of a food by taste.
  16. Mucranoid: A colon implant that is activated by medication, causing the Marine to excrete oily sweat that protects against extreme temperatures.
  17. Betcher's gland: A paired mouth implant that secretes a corrosive poison, allowing the Marine to blind enemies by spitting and even disintegrate inorganic materials (such as a chain, given time).
  18. Progenoids: Two progenoid glands are implanted; one in the neck and one in the chest cavity. These glands "mature" in 5 and 10 years, respectively, and contain the Chapter's gene-seed. Progenoids must be recovered in order to create more Space Marines. They are the closest Marines ever get to reproduction.
  19. Black carapace: The final implant is a black film or sheet which is implanted under the skin of the torso, where it hardens and connects with the Marine's nervous system. Interface ports are installed later. The black carapace is required to use Space Marine power armor properly - perfectly in-sync with the organic body.

As the neophyte is being implanted, other treatments begin. Chemical (i.e., drugs) and hypnotic therapy is required for the implanted organs to work properly. The neophyte will be indoctrinated and subjected to rigorous training. He will learn to control his new physique, command his implants, think and react faster, remember clearer, suppress pain and fear. This process is dangerous by nature, and even more so because of loss of understanding of the methods and techniques involved. Some of the operations and other procedures may be ritualized and poorly performed. Thus many of the neophytes will not survive.

When the initial process is finished, the neophyte becomes an "initiate". He will now serve as a lightly armored Scout (normally in the 10th Company) while his training is continued. He must improve the control of his mind and body as well as gather substantial battlefield experience and familiarity with different weapons. This stage may take years, even decades.

When the initiate is considered to be ready, he will become a "brother" and finally wear full power armor, typically serving in a Devastator Squad to master ranged combat, and then in an Assault Squad to gain skill in melee.


CodexAstartes organization

The Codex Astartes standard of organizing a Chapter

After the Horus Heresy, the original Legiones Astartes – the nine Legions still remaining – were reorganized according to Roboute Guilliman's Codex Astartes and split into smaller Chapters. One of the new Chapters, referred to as the Founding Chapter, kept the name of the old Legion, while the others took new names and became the first Successor Chapters.

According to Codex Astartes, a proper Chapter is organized into 10 companies of 10 squads of 10 men each, setting the strength of a fully manned Chapter to approximately 1,000 Space Marines plus commanders and support personnel. Each Chapter has the resources to function as a completely autonomous force with its own space fleet and other necessary matériel.

A Chapter is commanded by the Chapter Master, who has his administrative staff and other necessary personnel at his disposal. Each company is commanded by a Captain and assigned a Chaplain and an Apothecary. Additionally, there are the Librarium – the Librarians – and the Armory, which is maintained by Techmarines and Servitors. The companies of a standard "Codex Chapter" should be divided accordingly:

  • 1st Company (Veteran Company)
    • Veterans deployed as 20 Terminator squads or 10 Tactical squads
  • 2nd to 5th Companies (Battle Companies)
    • 6 Tactical squads
    • 2 Assault squads
    • 2 Devastator squads
  • 6th and 7th Companies (Reserve Companies)
    • 10 Tactical squads
  • 8th Company (Reserve Company)
    • 10 Assault squads
  • 9th Company (Reserve Company)
    • 10 Devastator squads
  • 10th Company (Scout Company)
    • Scout squads (number depends on recruitment rate)

Adherence to these guidelines varies between different Chapters. Some (such as Ultramarines) hold to them rigidly, some partially, and some (such as Space Wolves) openly scoff at them.

See alsoEdit


  • Cavatore, Alessio et al. Warhammer 40,000: Rulebook. 5th ed. Nottingham: Games Workshop, 2008. Print.
  • Priestley, Rick & Thorpe, Gav. "Rites of Initiation: The creation of a Space Marine." Index Astartes. Nottingham: Games Workshop, 2002. 2–9. Print.