Ultramarines - The War-Born: The XIII Legion's origin lay, as with their fellows, on Terra and the closing years of the Unification Wars. Extant records from this time show the XIII Legion's "Alpha" intake -- the test bed raising of several thousand warriors by which its gene-seed's stability and adaptability was judged -- was passed firmly within acceptable parameters and with no singular or notable physical mutation beyond the expected pattern, with full functionality of implanted organs to projected specifications.Psycho-organically, initiates were noted to display increased aggression, as was expected, but also a marked tendency towards cohesion and the adoption of hierarchy, alongside an almost pathological dedication to the achievement of an assigned goal, particularly when compared against the psychological profiles of certain other alpha samples such as those of the XII and V Legions (later known as the World Eaters and White Scars, respectively), who demonstrated more markedly heightened individualistic and fractious tendencies post-implantation.Although much of what would then transpire for the XIII Legion's very early expansion past its test stage has been occluded by layers of the unbreachable secrecy inherent in much of the Emperor's ancient gene-work, and records lost in the destruction caused on Terra by the great siege of the Imperial Palace during the Siege of Terra, certain facts can still be pieced together and a hypothesis formed.In terms of recruitment, evidence is apparent for a net being cast across Terra for initiates for the XIII, with intake from areas as diverse as the sub-equatorial maglev clans of Panpocro, the war families of the Saragon Enclave, the proud Midafrik Hive Oligarchy and, most latterly, the anthropophagic tribes of the Caucasus Wastes.As varied in culture and origin as these groups were, they all had one factor in common: their violent and often bitter resistance to the later stages of Unification, a resistance broken ultimately in each case not by negotiated surrender but near-annihilation, with, in some situations, little remaining save interned refugees and orphaned populations left by the savage conflicts which had brought these peoples to heel.It was this which led to the first informal cognomen by which the XIII Legion was known by the forces alongside which they served -- "the War-born." It may then be theorised that the particular psychological effects of the XIII Legion's gene-seed may have been used deliberately as a final weapon of the Unification to bleed away potential rebellion on Terra, and also further absorb the strength of the savage tribes of Old Night into the fledging Imperium.Further evidence for this can be perhaps inferred by the fact that no evidence remains of the XIII Legion seeing active deployment on Terra itself during the Unification Wars' bitter dregs -- as both the VII and VIII Legions' (later known as the Imperial Fists and Night Lords) early incarnations were, for example -- with their first full battle honours recorded as being for the First Pacification of Luna, and the brutal Sedna Campaign at the edge of the Sol System.As the earliest phase of the Great Crusade, the liberation of what became the Segmentum Solar, progressed, it was discovered that this ancient and most heavily settled region of the first stellar domains of Humanity held many survivors from the Dark Age of Technology.Of these there were some who openly welcomed the Imperium as patron and protector, but there were also many Human colony worlds who resisted Imperial Compliance, either through ignorance or prideful assurance in their own strength, just as there were others who were enslaved under the yoke of xenos oppression. The tide of conquest however, with the Emperor at the head of the war effort, quickly gained rapid momentum, and the fledging Space Marine Legions undergoing their first great expansion were a key part of this.During this period the XIII Legion, then around 8,000 Astartes strong, began to make its mark by taking part alongside other Legions under the Emperor's direct generalship, gaining renown in notable campaigns such as the Liberation of Diurnus and the destruction of the Scorvidian xeno-empire, as well as amassing a string of successful Compliance actions in solo operations on planets such as Lorin Sigma, Sekel's Landing and Ne'deble. From each of these conquered Human worlds, the most militant factions provided additional intakes of recruits tithed for the XIII, much as the war-born sons of Terra had infused their first intake.It was during this early period of the Great Crusade that the genius of the Emperor's grand design for His Space Marine Legions became increasingly apparent. While each of His transhuman cadres proved itself able to fight on any battlefield and achieve victory, the Emperor had clearly patterned in the alchemical mix of His gene-sons a diversity of tempers and abilities that had given each Legion a particular tactical strength or suitability to a theatre of war of its own beyond that of its peers.In some cases these talents were atavistic and visible, be they the near-preternatural fury already being displayed by the IX Legion (Blood Angels) or the uncanny resilience of the XIV Legion (Death Guard). In others they were subtle and bred in the bone, such as the oppressive darkness which consumed the souls of the VIII Legion (Night Lords), and they could manifest in word and deed to the ruin of their foes, or the unyielding, cold passion and technological aptitude of what was already becoming known as the "Iron Tenth" (Iron Hands). It was into this latter category which the XIII Legion fell.In them was found a mixture of aggression and restraint, discipline and determination which rendered them supremely suited for joint taskforce operations and cross-theatre warfare. The Legion also gained significant success in independent operations where it took direct command of the secondary mortal support forces of the Imperialis Auxilia, whether the professional and elite regiments of the Solar Auxilia and the regiments of the "Old One Hundred," or the often resentful and fractious hosts of Imperialis Militia auxiliary recently forced into Imperial Compliance.In the latter case, the XIII Legion often detached cadres of its own warriors to act as provosts and disciplinarians if needed, handing out final justice to the recalcitrant and inspiring bravery from the front lines; duties at which many other Legions baulked at as beneath their honour or as a poor use of Legiones Astartes in battle. In their adaptability and range of operations, they were said to be reminiscent of the vaunted I Legion (Dark Angels) and the prominent Luna Wolves. The key to their fighting style was imitation and adaptation.Their own arts of war had evolved quickly from the tenets laid out during their indoctrination and training, becoming combined with influences drawn from the host of martial cultures from which they were founded and the other Legions alongside which they served, from the knife-craft of the Opaki gangs of Hive Kôr to the armoured warfare tactics of the X Legion.