Space Marine Morphology

posted: 12th Aug, 2007 - updated: 1st Feb, 2013

Intro - Design Aims

The design of this marine is to match the official marine armour template created by the legendary Jes Goodwin. It seeks to justify the image of Space Marines 'as is' in the background and draws upon information known about the Space Marines in published material and comments by the design studio. My aim was to create a marine that is 100% compliant to the Warhammer 40,000 background, and explains some of the 'rule of cool' quirks - like marine heroes always seem to be 'bigger' than other marines, and the discrepancies between stated sizes in the background.

This work is a fan fiction 'hypothetical', one possible explanation that while unofficial does support the marine as seen in Warhammer 40,000. The marine armour template used is 100% Games Workshop, and the derivative 3D I model created from this template was used in the creation of cover artwork for the Black Library such as the cover of 'False Gods'. However I have never been asked to create and image of an unarmored marine - to avoid any confusion;

What follows is unofficial fan fiction...

Space Marines and Power armour

The marine morphology goes far beyond what we consider, with our modern day perspective, the limits of human body extremes. Yet the humans of the Imperium during 40K as not unfamiliar with humans that fall outside of out preconceptions; as they are not that rare. The largest of the super massive morphs of human are the classified as 'Ogryn' which even best marines for sheer mass. As such, the human population cline contains extremes that fall outside our current cline. Some of these new extremes of body type are the basis of the marine. Almost no one alive on the world today could even become a recruit!

Armour Match up

I started out with a template of the standard marine drawing by Jes Goodwin. This is GW official template and shows the correct proportions of a marine. I used this as my base template and repositioned the legs to be closer together for modeling purposes. My aim was to match a marine design as closely are possible to this template while maintaining a shape that would allow a suitable 'marine' body to fit inside. Some modification to the design had to be made to make the body look reasonably proportioned and suitably heroic (strong man), but I hope the feel of the marine has been retained. Jes discusses his view of marine design in the forth installment of the design studio podcasts: Design Philosophy IV: Jes Goodwin Interview. In it Jes says he thinks of marines as 7' to 7'6" with a mass of four basketball players 'bolted together'.

Space Marine armour matchup

Armour and Marine

[Notes: The armour is designed to be a second skin and fully integrates with the marine via the Black Carapace interface. The power armour has similar thickness to a modern day IFV or APC, though using advanced ceramics, and offers excellent protection against small arms fire. To offset the weight the armour is powered. This motive power is provided by Neuro-Fibre Bundles sandwiched within the superstructure frame plates, under the ablative armour plates]

Flesh vs NFB/ MW (Neuro-Fibre Bundle/ Muscle Wire)

[Notes: Muscle wire is incredibly powerful but uses tremendous amounts of energy to produce that power. This is a problem as the muscle wire bundles can drain far more energy than most portable systems can supply. While is is theoretically conceivable to build an android out of muscle wire (Iron Men) there would be no power system compact enough to run the android and keep it mobile (technology lost). Therefore relatively little muscle wire is used in power armour, and in marine armour the ratio of power and power system is carefully balanced and optimised.

The muscle wire is routed through the armour plates themselves. Each wire or wire bundle runs in a channel sandwiched between the inner and outer armour plating. The stops the wire slicing through the marines own flesh like a cheese wire. It also means that power armour can seem thin, as their is no underlying 'muscle suit' between the marine and the armour, the armour is self contained and the 'under suit' does not have any muscle wire (Black Carapace interface, sealed, hygiene, comfort, coolant).]

Marine diagram with skeletal and musculature overlay

This diagram shows an overlay of the marine skeleton over flesh, which in turn is overlaid onto the armour. The armour is modified to my personal preference of the Rogue Trader style marines. The most notable change is in the design of the armour covering the legs, hip exo-supports and faulds (hip armour). I drew heavy inspiration from the 'Rogue Trader' armour style.

Space Marine armour fitting

Muscle Mass Comparison

This chart is to give an idea of exactly how massive a marine is compared to a regular sized (real world western average) human. In full armour (far right) the marine is significantly more massive than the regular human on the far left. Much of the marines power is not 'magical' but due to sheer bulk and the increased muscle leverage due to the placement on the modified skeleton. The Marine's muscle leverage and resulting strength is strong in the same way a chimpanzee's or silverback gorilla's body is strong. It's not magical just damn powerful by design!

Power: Combined with their power armour a Marine would find it very easy to move a regular human, a shoulder barge would go though most 'blockers' and most doors! A punch would likely to take a regular human off their feet and hurl them several metres through the air. A Marine is massive enough to grab a regular human by the ankles and wield them like a cheap club to beat their way through a crowd (until the regular human disintegrated from the impacts, but in a crowd there are plenty of 'weapons'! As humans are 'bendy', they're probably a bit like wielding Nunchaku in a round about way smiley )

Space Marine Compare


Growth and Maturity [optional]

This section deals with the variations in marine size found throughout GW publications. It's entirely possible for such variations to be natural. Some marines may simply grow taller than others. This does raise an interesting curiosity should this be the case, that in 40K: marine heroes tend to be depicted as being taller than 7' and more often 8'.

Quote Jes Goodwin, podcast 4, 30:26
"I say 7 to 7 foot six, because actually if you read the novels they get progressively bigger every time we write a novel."

It could be that the larger marines are more heroic? This would further play into Western ideals of heroes being exceptional by bloodline, and there is nothing wrong in that interpretation, but on its own I find it a little 'narrow' in vision. It could do with some more variations added into the pot. What follows is an additional way to explain why marine heroes tend to be taller. It can be used in conjunction with the first.


Marines are the 'sons' of their Primarch. The Primarchs where very tall; it is said that a Primarch is as tall to a marine, as a marine is to a man. As a man is transformed into a Marine they take after their Primarch, growing taller and stronger over time. Often they pick up physical features and personality traits of their progenitor. The longer a marine survives the more like their primarch they become. The idea that follows plays into that by extending the assumed end of the transformation process. Instead the transformation process continues to affect the marine in some small way even after they have become a full battle-brother. I'm not suggesting that a marine could ever become a Primarch, merely that the transformation process takes a lot longer to wind down.

Note: This concept can be used for specific Chapter traits. One example is the Blood Angel's curse. This is where an Angel becomes destined to fall into the Black Rage due to their Primarch's death scream. As the transformation process continues to affect them, sooner or later, they will become so in tune with their Primarch's psyche: that they start to see visions. This may be due to the Blood Angle's practice of blood transfusion during the early stages of the transformation process - where they mix a little of their Primarch's blood in with their own. This may allow a shattered warp image of their Primarch to cling to the small portion of his (actual) blood running in his son's veins. His blood is kept alive within his sons. The longer the marine lives the more influence their Primarch has, and a Primarch's soul (even a fragment) is far too powerful for a marine.

Back to the concept;


Due to their rapid bio-recovery systems a marine is always in a constant state of rejuvenation and continues to grow for many centuries after completing scout training. Though their growth will eventually decline with age, it takes millennia for the marine bio-systems to reach a state of 'dynamic equilibrium'. Due to their work it is highly unlikely a marine will ever be in a state were age debilitates them. Even the great Lord Commander Dante, Chapter Master of the Blood Angels is still growing, but at a greatly reduced rate. His healing bio-systems are still top notch and he could survive for many millennia to come. It is also notable that now he is 'mature' for a marine he is starting to develop minor psionic powers such as precognition and looking ever more like his beloved Primarch and the most holy Imperial Archangel: Sanguinius.

Space Marine Growth

Stages and Height: Marine scouts are a minimum of 7', most tactical marines with a century under their belt are around 7'6". After this the growth rate slows but doesn't stop and the chapter heroes who are many centuries old are around 8'. Very few grow past 8' (ignoring genetic anomalies).

  1. Normal Human: This is a human of 5'9". No marine initiate is of this size and the growth line is marked by a dotted line.
  2. Neophyte: A marine is taken from exceptional fighting stock, often humans of a minimum of 6'6" with many being closer to 6'9". It is rare for humans larger than this to be taken as often such great size is down to growth defects rather than a stable gene pool of feral warriors.
  3. End Phase neophyte (Scout): This is the Neophyte in the end phase of training and the minimum height when a marine gains the final implant of the Black Carapace. Each suit of Space Marine power armour is customized to fit using pre-sized modular components, however no modular components are made that would fit a frame of less that 7'.
  4. Marine: Marines still grow for the first couple of centuries, during this time their custom armour is upgraded at regular intervals of around 5-10 years. As they grow and 'shed' armour, their armour plates are passed down to up and coming marines, and the now larger marine accepts the gift of armour components from more senior battle brothers. The passing of armour plates is a bonding ritual. This is also the time when most new marines are lost in war, and many of the armour plates given to marines is 'new' issue or reconditioned (repaired battle damaged armour salvage). This further increases the honour of receiving a 'cast off' from a big brother who is living, with such plates seen as 'blessed'.
  5. 'Terminator'*: Once a marine reaches an age of 2 centuries or more; their growth rate is practically zero. They no longer have to change armour plates, and their armour gains more and more honours becoming exceptionally ornate. At this level the armour is only handed on after death. It is these 'fully grown' and stable marines that can fit into, and are entrusted with, the greatest of the Chapter's armour relics: the mighty Tactical Dreadnought Armour.

* Apart from the Space Wolves

Armour Notes: Marine armour needs to be increased in size as the marine grows. Armour plates contain spacers between plates at joints (if you filed of the paint you could see 'growth rings' on the armour. A Marine who is 8' can be considered 'mature', but most will not make it to this age. The average marine is around 7'6", but ranges from around 7'3" to 7'9" for a tactical marine during their service. Most of their early and rapid growth is taken up during scout training (hence the scout style of armour which is free plates and cloth, (they could have used regular power armour like the technology interfaces used in the Sisters of Battle armour for training, and this would make a lot of sense if resources where unlimited, but the scouts grow so fast and die in such huge numbers it is impractical).

The undersuit of the armour is quite flexible when upgrading and usually only needs re-tensioning and added fibre bundles spliced in when needed, and resized anchors. This means a marine usually retains their undersuit throughout their exo-armour upgrades.

Terminator Honours, Allocation of Armour, and size

Most chapters will only allow those marines who have proved themselves time and again in battle, and who have long service records, to gain Terminator armour honours. In the process of proving themselves worthy, by acquiring honours, the marine matures and usually is at least a couple of centuries old before they have enough chops to gain Terminator honours. Even so, there are limited numbers of Terminator suits. Actually getting to wear the Terminator armour is not just being about age and size. Due to the limit stock only the current 'best of the best' will be allotted Terminator armour as needed. A marine may receive full Terminator honours and training and be eligible to wear Terminator armour, but never get to wear a suit of Terminator armour in battle as there are those in line before them with more 'honours' than themselves. Due to this limitation many fully mature marines with Terminator honours wear power armour instead. As such, any marine will have to survive long enough to see a senior brother to die before they can take his armour.

This whole process means that most Terminator honoured marines are taller than regular marines, and seem much taller due to Terminator armour being bulky and adds more height than power armour (a regular marine would seem taller in Terminator armour than power armour). A Terminator marine is very tall, and this gives a full range of 'marine' height of 7'6" to 8' in power armour, and as tall as 9' for an 8' senior marine in Terminator armour. As an aside, Terminator armour is restrictive compared to power-armour, and this suits the older marine as they are slightly less agile than the younger marines, so there is no loss.

Physical Power

It should be noted that while the marine is large, they are not built like a body builder. The skeletal frame of the marine is restructured to produce the morphology shown in the previous diagrams. Their musculature, and the power the marine can generate, is fundamentally different to that of a body builder who are 'muscle bound' (over muscled). A marine is not strong like a body builder; the are strong like a power lifter, and share a similar frame though much larger. The marine is also not tall like a person suffering from gigantism, which builds on a weak frame for the height, they are tall as if it was their 'natural' height (though there is nothing natural about a marine!)

Frame and Agility

To get an idea of the power of a marine think 'gorilla'. A very large silverback gorilla will usually top out at around 450lbs. The marine is around 780lbs, but has a bigger chest and legs, so the marine's arms are probably similar is power and size to a silverback gorilla. Which brings us to the question of agility - how can a bulk as large are a marine be agile?

The are a number of reasons, first: ever seen a gorilla charge? They aren't slow! Even bounding along on all fours they can cover ground quickly and easily catch a human (and barge through undergrowth like it wasn't even there!). A Rhino is pretty big but can outrun a human. Half a rhino is pretty heavy; so regular bone and muscle can support quite a bit of weight on two legs. A marine is probably physically able to run as fast as a human, maybe a bit quicker due to the length of their stride.


A marine is very large and fast which is great for a punch up, but not so great in war. The simple fact is that humans have been taking down animals which are far larger and faster than themselves since they first evolved (or created). If humans can kill tigers and woolly mammoth, a human the size of the marine is not a problem, in fact even our myths glorify taking on those larger than ourselves: David and Goliath. Marine's size alone is not threatening to a human warrior, they may be intimidating if you yourself are unarmed and unskilled, but a warrior would see it more as a 'challenge'. I'm sure a hero like Achilles would not be intimidated in the slightest.

What makes a marine powerful is not their size, it is their gear and their training. The gear is interesting because a marine is so large and their hands so big they would have trouble producing the gear they wear. Marines rely on regular humans to manufacture their gear. Without their armour covering a marine is highly vulnerable to weapons fire - but why so big?

Two reasons; one is that it allows them to wear thicker armour and this thicker armour is enough to defeat most small arms carried by humans and biped aliens alike. This means a marine is virtually immune to the vast bulk of an enemy's firepower. To get an idea, a marine is covered in armour that is superior to modern APCs or IFVs. A marine is effectively a one man IFV!

Second they are running around in STC structures which can accommodate their size, and makes it difficult to bring heavy weapons fire to bare. Though marines in novels are often running about in the open, this should be thought of as an exception (it's dangerous, perhaps reckless, but makes for good drama as the marines will face powerful weapons). Charging around STC bunkers (often a marine target) the marine will face small arms and the occasional hard point. They can therefore be very fast and 'reckless' (by regular human standards for similar situations) and take down and enemy HQ very quickly.

Notes: Interesting correlation between the primitive warriors of size and the techno barbarians of Terra; as the techno-barbarians would have the technology to protect themselves from attack and so could be large. Whereas in the greater galaxy most humans lost technology,and hence the advanced armour, so they would become vulnerable and thus the large may die off and the smaller humans survive and prosper. If this is the case then marine recruits can't be taken from worlds that lost technology, and instead are taken from the only place large humans of the right body frame exist: worlds with 'ogryn' like tenancies (I would guess than Catachan warriors, who are seen as 'baby ogryn' may be too large to start the process) It may be interesting to explore this aspect, as the techno-barbarians may be more about honour than real warfare - i.e. two leaders fight to the death and the winner takes all, thus reducing the loss of life. This means the techno-barbarians are 'champions' of powerful cartels and corporations who fight in vicious gladiator matches to win rewards.


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