FOUNDATION OF THE IRON WARRIORS

The Fourth Legion had its first members recruited from the gun-tribes upon Terra and prove themselves during the Unification Wars. Their domain would be a stalwart bastion for the Emperor of Mankind and establish early on their propensity for siegecraft be it defending a fortress or assailing one. Their Gene Seed was above average in its adaptability and was not adverse to Bionics, allowing for the Iron Warriors to enter the Great Crusade as one of the most numerous Astartes Legions.

Early in the Great Crusade the Iron Warriors would distinguish themselves during the conquest of the Sol System, in the process earning the privilege of having first access to new technologies and equipment from Mars. Despite their early successes the inflexible doctrines of the Iron Warriors would prove detrimental as the Crusade expanded and called for new approaches, with the Astartes of the Fourth Legion continuing to use siege and attrition warfare to solve whatever conflict they came across. This was in part due to the stubborn nature of the Iron Warriors, but also due to what others criticized as a lack of imagination including the Primarch Horus himself.

Despite, or rather because of, their rigid nature they would receive praise from Horus as that very stubbornness made them naturally suited for the times the Great Crusade did require dull but important wars of attrition. Where other Legions could falter in time or act rashly beyond the orders given the Iron Warriors instead would do as told and through tenacity overcome the obstacles placed before them, finding victory through outlasting their foes rather than through quick decapitation strikes or through the usage of other rapid deployments favored by other legions such as the Luna Wolves.


IN A COLD, FAR AWAY WORLD

Seemingly for this same reason the Fourth Legion would have its forces spread out and garrisoned on many worlds, as well as engaging in smaller and more local campaigns as called for, for they could be relied upon to do such thankless tasks. One such campaign was for the frigid wasteland of Kimara, a planet sparsely populated by pockets of humanity who settled there to obtain its valuable natural resources. Unlike other worlds Kimara did not need to be subjugated when encountered by the members of the Great Crusade, instead willingly joining with the Imperium when given the opportunity on the condition of receiving their aid in repelling various threats to their people.

This request was made due to how vulnerable the citizens of Kimara were to raiders from other worlds given the planet's low population size and the constant threat its local wildlife posed by it vicious leviathan creatures or be it aerial predators whose packs could tear apart trained militia like they were as soft as the snow falling upon the landscape. Both Xenos and Human raiders regularly pilfered Kimara, presenting a common nuisance that threatened to deprive its people of what little they had. The cold of Kimara was relentless and unforgiving, being lethal to even Astartes given time, so it was far easier for pirates to obtain the planet's resources by killing those who mined and processed them in the first place.

Kimara's government was largely feudal, resembling the kind of society once possessed by humanity in the Medieval era as it served their needs best: allowing various territories to self-govern let them react better to the individual threats they faced, while for larger problems the planet's ruler could rally his subjects from wherever needed to combat it. With no room for dissention or particular selfishness in the early years of Kimara's settlement its people would become known for possessing personalities as cold as their world, doing what they were told and rarely interacting with those outside their immediate social or work spheres. Even their skin was remarked upon as being a reflection of the world, being as pale as the outside snow thanks to how little natural sunlight they could receive without dying immediately from the climate.

If they were more individualistic it could cause conflict, which in turn could threaten the lives of all who lived in their particular cities lest it damage their carefully maintained environments within the cities, so it is perhaps this reason that they would find common cause with the Iron Warriors: both were known for icy behavior towards others while still being stubborn, driven, and relentless to a fault even in the face of extreme adversity or suffering. They would do what they were told even if it was thankless and would require sacrifice on their part, and so once united the forces of Kimara formed a seamless machine with the Iron Warriors sent to aid them.

Living inside and almost never being exposed to greater society caused the archetypal traits of Kimara traits to grow in its population over time, and it made them natural counterparts to the inhabitants of a nearby planet of Wostyn which was completely covered in desert just as Kimara was in snow and ice. While Wostyn itself was merely on poor terms with Kimara, pirates hailing from it would become the bulk of those raiding Kimara since it was an easier way of life than living off what little their home planet possessed.


ONLY THE STRONG WILL SURVIVE

When the first Iron Warriors were stationed on Kimara under the command of Kydomor Forrix it was at the peak of the planet's pilfering by outsiders. Rather than try to chase down

the raiders whose swiftness was their primary strength the Iron Warriors saw fit to reinforce the cities, assign guards to their convoys, and to wait for the Wostyn pirates to come to them: in time the pirates would have their numbers all but eradicated, unable to wound the Astartes now guarding Kimara, and so Kimara's people were freed from their primary threat and the Iron Warriors hailed as heroes. While unused to actually receiving gratitude the Iron Warriors accepted it gracefully from the soldiers they fought alongside and civilians they protected.

This was not the end to their troubles however, as Kimara had erected its fortress cities for more than refuge from the cold: they were in fact primarily there to help protect them from the planet's deadly predators. Serpent-like beasts larger than a Baneblade regularly threatened their settlements, these Yormungaros as they were known laying waste to all in their path and sparing none during their vicious rampages. Then there were the Hoarfrosts, winged monsters which hid amidst the cloudy skies before swooping down to attack their prey with their freezing breath and sharp claws. Lastly, the seas were

plagued by what few survivors would describe as 'Krakens', giant squid-like beings so massive they dwarfed the Yormungaros and who posed a threat to shipments moving from one region to another.

The skies of Kimara were too dangerous to travel due to their predators, vicious winds, and unrelenting storms. The seas ravaged by creatures few lived to tell about after first surviving the gargantuan waves. Even the land was hampered by constant snowfall and merciless monsters it would make one wonder why Humans would want to settle on such a world at all: the answer to that was a rare resource by the name of Mithril. It had been located on other planets previously, but never in any significant quantities until the point where it was thought gone by the Imperium...until Kimara's first settlers rediscovered it and used it to then survive on the unforgiving world.


THE PEARL OF KIMARA

Mithril, a silver-blue metal, drew its value from its ability to be used for a myriad of purposes, the most notable and common of which being as armor: while its qualities allowed for it to be forged into weapons superior to their normal counterparts, the ability of Mithril to shrug off most forms of damage made it not only hard to mine but also extremely effective at ensuring the survival of whomever wore it in battle. Its natural resistance to both heat and the cold allowed it to be used for soldiers to be deployed on Kimara itself, and many of their elite officers wore it for missions out into the cold wastes of the planet where seemingly nothing but snow and ice awaited them.

The many positive aspects of Mithril were weighed against various negatives: the metal required to fashion a suit of armor was heavy enough that if worn by an Astartes even they would have their movement significantly reduced, and it took special training for a normal Human to wear it without having to take breaks to rest from its weight. In addition the same aspects of Mithril which made it difficult to damage in battle as well as resistant to both cold and heat made actually turning it into armor a time-intensive process that was simply not practical to the needs of the rapidly expanding Great Crusade at the time. Lastly, due to the nature of the planet itself, Mithril was hard to come by and Kimara did not yet possess enough industry to excavate it in a quantity great enough to fashion thousands of Astartes like Forrix had at one point hoped to.

Rather than continue pressing on with the Great Crusade Forrix instead invested some of the resources afforded to him on building up Kimara's own infrastructure, allowing the natives to fend for themselves better once their cities were protected by an array of Basilisks and Hydras to fend off their predators. To assist construction, units of Iron Warriors would proactively cull many of the bestial threats over the course of the months it took to build up the local defenses and military. During these outings Forrix would come to be impressed by a young local by the name of Trahaearn Jarn, who despite his age was assigned by the local military forces to guide the Iron Warriors to the dens of various beasts so the monsters could be slain as they slept to reduce allied casualties.


A/N: Games Workshop used to sell a paint titled Mithril Silver, but it has been replaced (likely for copyright reasons) with "Runefang Steel". Since this codex is dedicated to bringing back a lot of things sort of abandoned or ignored by GW, I figured the valuable resource ought to be another such thing. I based its color in this universe off of GW's silver mixed with Runescape's blue Mithril, so it's a sort of grey-blue here.

This information will serve as the background fluff that one usually sees in a fluffy codex prior to it discussing battles and more recent history, though we are not quite done yet with the background since I am trying to be thorough. Remember that if you want to see the actual codex pages you can visit Spacebattles or ArchiveOfOurOwn where I am able to share images!

This codex is a work in progress, so I hope you are enjoying it and will let me know your thoughts below!