Space Marine Legions - Legion Integration and Development: The Legions of the Great Crusade were a fusion of dual natures. They were the product of the Emperor's conquest of Terra and the Sol System. Selected from Terran stock and moulded by the wars of the nascent Imperium, these Legions held a certain commonality of character.A sense of unity and an almost familial bond pervaded their ranks. Given that they were all of the first generation of Astartes, born of Terra, they shared the imprint of their genetic forging and warlike history, and it is no surprise that members of the early Legions regarded each other as siblings, as brothers-in-arms.Training, indoctrination and the shared experience of battle reinforced this belief within the Legiones Astartes, encouraging the idea that they were a family born in the cradle of war. This bond of brotherhood would survive as the Imperium grew, but perhaps it was never as strong as it was when the Legions first conquered the techno-barbarians under the Terran sun.The second face of each Legion was that of the people and cultures which had flourished under different stars. As the war to unify Terra became a crusade to conquer the galaxy, the Legions grew. Casualties had to be replaced, and as the wars grew in scale so too did the number of losses and the number of recruits that were needed to take the places of the fallen.Initially intakes were drawn from Luna, Saturn's orbital stations, the Proximal worlds, and dozens of other worlds of the near Segmentum Solar fed the Legions' needs for warrior stock. As this occurred, the Terran foundations of each Legion became diluted but was never overwhelmed, for the warrior tribes and cultures of Old Earth were many and their commitment to the Great Crusade resolute.With the re-discovery of the Primarchs and in many cases newly adopted homeworlds used as Legion fiefs (most commonly the worlds upon which a Legion's new master had been found), this was to change the character of the Legions profoundly. Some alterations were superficial: a habit of speech, a change in close-quarter tactics, martial traditions and warranted additions to iconography and even language.But for others the change would prove dramatic, with entire paradigms of culture, tradition and even ideology overwriting what had come before, such as in what came to be known as the Space Wolves, Blood Angels and Dark Angels Legions.In many cases the stamp of the Legions and the will of the Primarchs on their recruits came to largely outweigh differences of birth or blood, but in other Legions such as the Luna Wolves and the Emperor's Children, a subtle divide would grow between those veterans who had been recruited into the ranks of the Astartes by the Emperor from Terra and those who had come into the Legion from their Primarch's homeworld. This rift would be one factor among many that would lead several of the First Founding Legions towards ultimate damnation.By the middle years of the Great Crusade the ongoing effects of these shifts within the Legions had resulted in a wide disparity in culture and organisation between them. The outward sign of this was the development of a distinct character which meant the original Terran military patterns they had adhered to at the outset of the Great Crusade had been largely abandoned or become so modified and diluted as to be in some cases unrecognisable.There were, of course, exceptions in whole or in part, such as could be found within the Ultramarines and Iron Warriors Legions, who built upon rather than abandoned what had gone before, as well as those such as the White Scars to who the strictures and precepts laid out by the Officio Militaris were no longer even notionally applied.There are those that have cited this increasing idiosyncrasy in hindsight as the seeds of division, of a sense of insularity and "otherness" growing between one Legion and another. This itself only fuelled rivalries and feuds that had begun to simmer beneath the surface of the Great Crusade, both between the Primarchs and their Legions, that would later be exploited by Horus and his heretical conspiracy, and lay them open to the introduction of the Davinite warrior lodge cult structures into those Legions he favoured. These warrior lodges were the avenue by which the stain of the Warp would later taint those Legions that turned Traitor.