The rank of Captain within the Legion also held subtle variations of authority. Generally those in command of a lower numbered company outranked those in a higher numbered company, while those who had once had overall command of a campaign were considered superior to those officers he had commanded during that action. At the top of this informal but very real hierarchy of Legion officers were those Captains who served as Horus' closest advisors and in particular the First Captain of the Legion who commanded the elite 1 st Company and also served as his primarch's principal field officer and second-in-command. However, following their corruption by Chaos, the Sons of Horus Legion's Space Marines started to exhibit random genetic mutations, and it is likely that this taint now affects their gene-seed as it has almost all of the Traitor Legions. The regular practice beginning in the Horus Heresy amongst the Legion's Astartes of seeking daemonic possession may also have accelerated the effect. The wearing of pelts of such augmented canid predators increasingly marked out the field commanders and officers of the Luna Wolves. The XVI th would not be the only Space Marine Legion to bear such a title and embrace this imagery as their own, but they were the first.

The XVI th Legion's homeworld, the ancient Mining World of Cthonia, no longer exists, having apparently lost geo-structural integrity and broken apart into asteroids and debris during the centuries following the Horus Heresy. Certainly the once ore-rich planet was riddled with mine workings right through to its dead core as the numerous gangers that formed the majority of the world's population may originally have been imported as work teams to maintain the crumbling tunnels.Jerrod - Replacement Captain of the 13 th Company after Luc Sedirae was killed on the world of Dagonet while he was fulfilling his role as a body double for the real Horus and was assassinated by a special Officio Assassinorum strike team. The changing icon of the Luna Wolves and Sons of Horus Legions, from the Great Crusade to the 41st Millennium. The Dark Gods portrayed themselves as victims of the Emperor's psychic might, and claimed falsely that they had no real interest in the happenings of the material world. Magnus the Red, the sorcerous primarch of the Thousand Sons Legion, had also travelled into the Warp via sorcery to try and stop Horus from turning to Chaos. Magnus explained that the Warmaster's vision was only one among many possible futures, but one that Horus alone could prevent. Many of these titles betrayed the culture of Cthonian gang honours and the tradition of reputation and internecine warfare from which they had sprung. This culture had grown steadily stronger over the years within the rank and file of the XVI th Legion's intake of Neophytes.

Even Horus, a generalist and a pragmatist, upon being given command of his Legion is thought to have adopted new squad formations after having seen their effectiveness in other Legions. For example, it is noticeable that until the Lactrical Onslaught the number of Storm Shield-equipped Breacher Squads was relatively low in the XVI th Legion. The contributions of such units amongst the forces of the Imperial Fists cannot have escaped his notice. Oblivion (Strike Cruiser, Unknown Class) - The Oblivion was severely damaged during Abaddon’s assault on Manachea Vysidae during the Manachean War. It is believed that the Oblivion was amongst the first vessels to be repaired at the recently conquered facilities of Port Maw. Instead of a formal structure, Horus would group companies and individual units together as required for the execution of a particular campaign. The commander of such a formation would usually be a senior Captain. If the formation was especially large, then other Captains would take on the role of lieutenants to the overall force commander until the completion of the campaign. These formations rarely had formal titles, but the Sons of Horus commonly referred to formations intended to prosecute a rapid assault as "Speartips."First Captain Ezekyle Abaddon ultimately managed to restore a measure of discipline to the XVI th Legion and bring its disparate warbands under his control after he assumed Horus' place as the Warmaster of Chaos, mainly through exercising a level of fear and violence that could cow even the greatest of the Legion's Chaos Champions.

Like most of the embryonic Space Marine Legions, the XVI th Legion drew all of its first recruits from the Terran population. Though it is difficult to be certain based on the existing Imperial records from this lost time, there are indications that many of the XVI th Legion's early intake came from the hunter clans of the Jutigran Bowl and the Samsatian sub-plate slums. Perpetual conflict and the harshness of life on the desolate margins of Terran society had given these people the hard edge of ruthlessness and independence that would serve a Space Marine well. In the aftermath of this Ullanor Crusade, Horus was granted the newly-created title of " Warmaster," the commander-in-chief of all the Emperor's armies who possessed command authority over all of the other primarchs and every Expeditionary Fleet of the Great Crusade. Before returning to Terra to oversee the next phase of the creation of his stellar empire, the Emperor suggested to Horus that he rename the XVI th Legion the "Sons of Horus," in honour of their primarch and to show his preeminent place amongst the other primarchs. The Luna Wolves were the first Space Marine Legion to begin recruiting from another world beyond Terra. In this case, the new pool of Aspirants was found amongst the adolescent human males drawn from the violent hive city gangs inhabiting an ancient former Mining World that had devolved into a Feral World called Cthonia. Cthonia was located in one of Terra's closest neighbouring star systems in the Segmentum Solar and was within reach of spacecraft that could travel at only sublight velocities before the invention of the Warp-Drive. He took up the Emperor's old offer and renamed the XVI th Legion the Sons of Horus after being convinced to do so by his brother Primarch Sanguinius of the Blood Angels Legion just before his experiences on Davin. Horus was now allied body and soul to the Ruinous Powers of Chaos, and he had a new vision for the Imperium with himself rather than the Emperor at its head.Other highly creditable claims state that the Emperor found Horus, the first of his lost sons, but neither source specifies where, or the location of this finding. Surrounded in millennia of myths and allegory, the truth of Horus' origins will more than likely never be known. As a result, Horus was for many standard years the Emperor's only son, and there was a great affinity between them. The Emperor spent much time with his protege, teaching and encouraging him. Horus was soon placed in command of the XVI th Legion, which had already come to be known as the Luna Wolves -- 10,000 Astartes created from his own genetic code. With these superhuman warriors to lead, Horus accompanied the Emperor for the first thirty standard years of the Great Crusade that had begun in ca. 800.M30, and together they forged the initial interstellar expansion of the young Imperium of Man. Refusing to believe that Horus, his most beloved and trusted son, would actually betray him, the Emperor instead mistakenly perceived the traitor to the Imperium to be Magnus and his Thousand Sons, who had long suffered from a near-debilitating run of mutations because of the instability of Magnus' own genome and were known to have practiced the sorcery that had been expressly outlawed in the Imperium at the Council of Nikaea several Terran years before. Severian - Severian was an Astartes of the 28 th Company who was incarcerated in the prison of Khangba Marwu on Terra after the outbreak of the Horus Heresy. Severian escaped from the prison along with several other Astartes of the Crusader Host. Severian was last sighted in the Petitioner's City on Terra and his ultimate fate remains unknown. Assault on Dahinta (Unknown Date.M30) - On the world of Dahinta, the Luna Wolves fought against a race of self-aware machines called the Overseers, who were led by the artificial intelligence known as the Archdroid. One of the Emperor's longest-standing commands was that no sentient machines could be allowed to exist, for they had nearly caused the extinction of Mankind when they had rebelled against their human overseers during the Dark Age of Technology. Despite heavy casualties amongst, the thinking machines were wiped from the face of Dahinta by the savagery of the Astartes. Only after the campaign had ended was the full truth learned: the Overseers had been created by a vanished offshoot of humanity that had settled Dahinta, perhaps during the Age of Technology. The Overseers had cared for their lost masters' crumbling cities long after they had become extinct or left their homeworld behind. In the time when the Emperor's eye first began to fall beyond Terra, He raised new armies to fight His Great Crusade to reunify all of Humanity across the galaxy. He drew these new troops in part from the forces that had already unified Terra during the Unification Wars of the late 30 th Millennium, from willing Terran volunteers like those who comprised the XVI th Space Marine Legion who were implanted with the gene-seed of their missing Primarch Horus like all the Astartes of the First Founding. These recruits were also drawn in part from the Emperor's subjugated enemies, and together they represented the first generation of Space Marines.