Groupmaster - History: The Indomitus Crusade would not be one vast fleet ploughing across the stars like some crude battering ram. Rather, Roboute Guilliman's vision called for an initial mustering of ten mighty fleets. These would be known as Fleet Primus, Fleet Secundus, Fleet Tertius, and so on, and each would be ruled over by a supreme officer bestowed the almighty rank of "fleetmaster."Each fleet was a unique mixed force, comprising elements of the various Imperial military factions in a balance dictated by Guilliman and intended to operate in a different fashion and to different grand strategic ends. The fleets varied tremendously in size and composition. Still, even the smallest numbered hundreds of sleek warships and twice that number of logistical supply craft, all gathered to facilitate the deployment of countless billions of fighting men and women.Expecting fleets of such size to operate as singular and coherent forces was impractical, Guilliman knew, and wasteful. What sense was there in attempting to hold such vast agglomerations of martial might together through the vagaries of Warpspace only to strike each fresh system with preposterous overkill?Even should the assembled Imperial forces not simply get in one another's way, they would undoubtedly crush a single enemy utterly in each instance only for myriad other threats to go unanswered. Rather than risk such heavy-handed foolishness, Guilliman commanded that each fleet be further broken down into a number of battlegroups that would be codified with High Gothic alphanumerics such as Battlegroup Alphus, Battlegroup Betaris, Battlegroup Cerastus, and so on. Each battlegroup would be a wholly self-sufficient formation with its own command ships and designated commanding "groupmaster" to direct its course and actions. The groupmasters of each fleet would answer only to their fleetmaster, and of course to Roboute Guilliman and the High Lords of Terra.Battlegroups would each pursue their own course within the wider strategic movement of their fleet, investing their own war zones and fighting their own campaigns. Their grand strategic movements would be dictated by their fleetmaster, and they would be able to request or supply reinforcement from and to the other battlegroups within their fleet.In most other respects each battlegroup would function as its own self-contained force, and most would still possess the prodigious martial might to conquer entire star clusters, annihilate xenos empires, and make war across multiple star systems at once. Thus, an Indomitus Crusade fleet pushing into a sector of Imperial space would resemble not the thrust of some huge lance but rather the multiple blades of a legion of swordsmen, driven point first into the shroud of shadows that veiled the Emperor's realm.A third, still-more-granular level of organisation was built into each battlegroup, that of the task force. These were not existing sub-formations in their own right, but rather specialised military groupings that could be assembled at the order of a groupmaster. Task forces would be formed for the prosecution of a single task, after which their constituent elements would return to their battlegroup and fragment again.Task forces were intended to achieve the conquest of specific worlds or defence platforms, the couriering of vital messages through the vastness of space, the destruction of specific enemies who had been marked for death, and whatever other important tasks had to be achieved in order to ensure the wider battlegroup's success.No two task forces need ever be entirely the same in composition, for their purpose was to concentrate precisely the right balance of intermingled Imperial assets into a single force to complete a single task. But in practice, as the Indomitus Crusade fleets pushed out into the Imperium, it quickly became the norm for especially successful task forces to remain together for the duration of extended campaigns, and for them to build ties of loyalty to one another that lasted lifetimes.There was another duty that Guilliman had in mind for his task forces, and it was a crucial one. Even as the grand muster of the crusade continued, he had the fleetmasters select elite task forces from amongst the gathering ranks of their assigned warriors. Each of these task forces was joined by a complement of Sisters of Silence, at least one squad of Adeptus Custodes, and a conclave of Magos Biologis who brought with them sealed and warded canisters and many strange, arcane-looking machines.The Sisters of Silence were there to drive back the Warp storms that plagued realspace in the wake of the Great Rift's birth and aid the voidships of their task forces in traversing the Imperium swiftly and comparatively safely. The Adeptus Custodes were envoys of Guilliman himself, speaking with the authority of both primarch and Emperor to ensure the task forces met with no political resistance from any Imperial body, including the Adeptus Astartes. Finally, the Adeptus Mechanicus Tech-priests were there to deliver that which they brought with them, the gene-seed and technologies required for their assigned Space Marine Chapters to embrace Archmagos Dominus Belisarius Cawl's Primaris Space Marine miracle.Often accompanied by awakened Primaris battle-brothers of the Ultima Founding destined to join the ranks of their target Chapters, these task forces sped out into the darkness even as the crusade fleets continued to muster in their wake. They would be known as "Torchbearers" to the beleaguered Imperium, and they would bring the blessings of the Primaris Space Marines to the most far-flung, the most embattled, and -- in a few rare cases -- the most recalcitrant or dangerous Chapters.