I've been creating some personally made background for the Pures present in my Veteran Mod in the Lost Chapter race. Some things are based on knowledge collected on Warhammer 40k but most is obviously personnal fiction.
Pures are genetically engineered clones of former space marines which live half lives growing up in half the time a regular human would but also dying of old age (if they ever get to that point) with approximately half the age a human would die with.
Unlike other cloning processes, Pures are not kept in their birth tanks until they reach adulthood but are rather taken away from them on what could be seen as the first months of life of an infant. This allows their creators to evaluate their behavior, physical and mental capabilities, thus taking notes of which among them learn to speak first, walk first, among other things. Any mental deficiency detected among the young Pures means the death of those Pures where it was detected (physical deficiencies are usually detected prior to the extraction of the Pures from their tanks being their fates similar). Pures which reveal a lack of development on the additional organs possessed by space marines are often sent to administrative roles or the local Imperial Guard/Planetary Defense Force since they are healthy but not worthy enough for marines.
Those Pures that remain are sent into the wild when they are around 2.5 years old and will remain there until they die or reach the age of 7.5 years old. After spending 5 years in the wild fighting each other and against the local animals and plants, the Pures skills are evaluated again and their final training begins. During this phase Pures with erratic behavior or incapable of following orders, even if they possess excellent skills in survival and combat, will either be eliminated or sent into Chaos infested areas to use ther incontrollable nature to destroy the enemies of mankind. Usually they are assigned to a specific chaos infested system for a century or two. This is because even the less desirable Pure is an awesome warrior and unlike most humans their connection to the warp is slim which prevents the clones from falling to Chaos. Few Pures ever return from these tasks due to the difficulty of a single warrior surviving even one day in such environments, let alone carry on a purge for over a century. Those that do return are received as heroes with the tales of their accomplishments being registered in the Chapter's archives. If their uncontrollable nature has calmed down, they might even be reintegrated fully in the Chapter serving in a position of honor. The job done by those Pures sent out to face Chaos, even those that never return, is invaluable for both the Chapter and the Imperium. Any amount of daemons and heretics they kill, warp portals they close or destroy and any planet they cleanse help in the containment or even anihilation of the chaotic servants in the area they were sent to.
Pures serve usually in small squads of up to 4 soldiers and depending on their skills they will either be a part of Pures squads or Assault Pures squads. Those that show aptitude for ranged weapons and usually also the best cognitive skills form Pures squads capable of destroying most enemies at a distance. Those that prefer close combat (and usually are controlled psychopaths) form Assault Pures squads possessing similar armour and wargear than other Pures but equipped with pistols and heavy melee weapons.
Blog under construction.
