Eidolon

Eidolon served as Lord Commander, one of the senior-most ranks within the Emperor's Children Legion during the Great Crusade and Horus Heresy eras. Eidolon was the first Space Marine selected by their Primarch Fulgrim to lead an entire company. Commonly regarded as the most proficient of all the Lord Commanders having been a dedicated student of the art of warfare in all its aspects. It was not generally known if he survived the Battle of Terra. Unsubstantiated rumours persisted that Eidolon yet lives; responsible for hundred, if not thousands of raids upon Imperial worlds for the last ten millennia. Unsubstantiated evidence suggest Eidolon has served as a lieutenant to Abaddon The Despoiler, a consort to Queen Sylelle as well as a Chaos Champion of the Daemon Prince N'Kari.

History
Long ago, during the turbulent era known as the Age of Strife, warp travel became impossible and all the worlds which humanity had claimed were cut off from one another, forced to fend for themselves without the support of their neighbours in other star systems. The Libram ex Dominar, one of the few surviving texts from this time, tells that Chemos was one such world, a mining colony dependent on interstellar trade for food. Following the end of Old Night the Emperor of Mankind first publicly revealed himself during a series of conflicts to reunite the disparate techno-barbarian nations of Terra, collectively known as the Unification Wars. Following their successful conclusion the Emperor began to forge the foundation of the Imperium of Man in the 30th Millennium. The Emperor began a massive scientific effort to create the Primarchs -- 20 genetically-engineered sons that would serve as the Emperor's generals and command the Emperor's forces during the Great Crusade to reunite the scattered human race beneath His leadership. Their genomes later served as the genetic template from which the Emperor crafted his 20 Space Marine Legions.

The Ruinous Powers of Chaos somehow manage to spirit the superhuman children away through the Warp, however, leaving them scattered across the galaxy. A massive localized Warp rift was created within the gene vaults of the Emperor's own palace, deep under the Himalazian (Himalayan) Mountains on Terra where the Primarchs were gestating. The gestation capsules containing the Emperor's unborn sons were scattered through the Warp to colony planets long since lost to Mankind. Each of the Primarchs somehow found themselves on ancient worlds of men, planets long since lost to the light of the greater universe beyond the stars. The infant Fulgrim, Primarch of the Emperor's Children Legion grew up upon the bleak, dying world of Chemos, a mining colony long fallen to decay and decline as Old Night claimed the domains of Mankind. Isolated from surrounding systems, the industry of Chemos had fallen silent, the mines replaced by the reclamation plants and vapour extraction facilities that kept the dwindling population from vanishing entirely. Within fifty years of his arrival on Chemos, Fulgrim had risen to become its leader, and it was his dream that the wonders of long lost ages might be rediscovered and rebuilt. However, it was only when the Emperor came to his world that the Primarch could begin to fully realise his vision. By that time, it was not simply his home world that Fulgrim desired to see elevated to glory, but the entirety of Mankind.

When Fulgrim was introduced to the Space Marine Legion that shared his genetic inheritance, he found not a resplendent host as did so many of his brothers, but a mere two hundred Battle-Brothers. An accident had befallen the nascent Legion early in the development of its gene-stock, setting it far behind its fellows. Eidolon was one of these surviving original surviving Astartes. Thus, it was necessary that Fulgrim and his warriors be integrated into the ranks of another Legion until such time as their numbers were sufficiently restored for them to take to battle on their own. The Legion to which Fulgrim and his warriors were assigned was the Luna Wolves, the Legion of Horus, and Fulgrim could not have had a better companion at whose side to master the arts of warfare.

From the earliest days of its service to the Great Crusade, the nascent Legion was recognised for its drive to attain perfection in all its deeds. It was in recognition of this drive that the Emperor granted the warriors of the Legion the right to bear the Imperial eagle upon their chest armour, a unique honour at that time. In recognition that the Emperor was the very pinnacle of the perfection Fulgrim aspired to, the Legion was named the Emperor’s Children, a title it would retain even after the calamitous events of the Horus Heresy.

Attainment of Perfection
Like his Primarch, Eidolon was driven by the impossible desire to attain perfection in all that he did. Eidolon accepted nothing less than perfection in all of his endeavours, and worked ceaselessly to perfect his Legion's military operations. Each and every Legionnaire trained every waking hour for his assigned task. In recognition of his leadership abilities, tactical acumen and drive for perfection, Eidolon was recognized by his Primarch and became the first Space Marine selected by Fulgrim to lead an entire company of the Emperors Children. As a company commander, he was further recognised for his superlative talents as a leader of men and was granted the esteemed rank of Lord Commander. The Primarch had personally chosen Eidolon and elevated him to this senior position within the Emperor's Children hierarchy, seeing in him the potential and qualities needed to lead the Emperor's Children. Eidolon was commonly regarded as the most proficient of all the Lord Commanders within the Emperor's Children III Legion. Until the corruption of the Legion, Eidolon dedicated himself to mastering all aspects of warfare. His troops fought equally well in sieges, holding actions, rapid strikes and grueling campaigns, never displaying any inexperience or inefficiency no matter what was demanded of them. Eidolon regarded Fulgrim as a father in the literal sense, considering his bond of gene-seed to be as strong as true parentage. Though he accepted that he could never equal the Primarch in power. Eidolon nevertheless spent every waking moment studying Fulgrim's tactics and strategies, his writings and orations, in the hope of being as close to his leader's perfection as he could possibly become.

Cleansing of Laeran
Shortly after the beginning of their own Crusade, the Emperor`s Children encountered a hitherto-unknown alien race upon the xenos planet called Laeran, officially designated as Twenty-Eight Three, being the third world the 28th Expedition had brought to compliance. Unbeknownst to the III Legion the Laer were corrupted xenos worshipers of the Chaos God of Pleasure, Slaanesh. Though the ocean world of Laeran would be of immeasurable value to the crusade of the Emperor its alien inhabitants did not wish to share what blind fortune had blessed them with. They had refused to see the manifest destiny that guided Mankind through the star and had made it abundantly clear that they held the Imperium in nothing but contempt. The III Legion's advance had been rebuffed with violence, and honour demanded they answer in kind. Fulgrim ordered his Lord Commanders to attack immediately, beginning a war that the Council of Terra predicted would last at least a decade.

During the ensuing campaign the Chief Apothecary Fabius Bile discovered upon examining some of the corpses of the Laer that the serpentine creatures had been engaged in extensive genetic engineering to perfect their species, creating a multitude of different castes who were genetically designed to best serve their intended function in Laer society. Bringing his findings to his Primarch, Bile explained that the Laer were not so dissimilar to the Emperor's Children in their approaches to perfection. He put forward the hypothesis that what the Emperor had made was incredible, bu what if it was but the first step on a longer road? Bile suggested that if they were to look upon their own flesh they could find new ways to improve upon it and bring it closer to perfection. The Apothecary may very well have signed his death warrant by speaking so frankly, but the possibilities that might be opened up were worth any risk. To attempt to unlock the secrets of the Emperor’s work in creating the Astartes would be the greatest undertaking of his life. Fulgrim inquired to Fabius Bile if he truly believed that he could enhance the gene-seed of the Astartes. The Apothecary admitted that he didn't know for certain, but he believed that they had to at least try, for by doing so they would move closer to perfection -- and only by imperfection would the Emperor's Children fail the Emperor. The Primarch agreed with the Apothecary's proposition and gave Bile free leave to do what needed to be done.

With the end of the war on Laeran, the steady stream of wounded and dead to the apothecarion had slowed, leaving Fabius more time to devote to his researches. To ensure the secrecy his experiments demanded, he had relocated to a little-used research facility aboard the Andronius, a Strike Cruiser under the authority of Lord Commander Eidolon. Its facilities had been basic at first, but with Eidolon’s blessing, he had gathered a bewildering array of specialist equipment. Eidolon had taken a personal interest in Bile's work, though he disapproved of his methods. Fulgrim had told the Lord Commander of the scale of what he was to attempt, for his work would enhance the physiology of the Astartes. Eidolon informed the Apothecary that when he returned from his more laborious duties, Bile would begin his experimentation on him. Through the Apothecary's genetic enhancements, the Lord Commander hoped to become Bile's greatest success, faster, and more deadly then ever before. He wished to become indispensable right hand of the Primarch.

Murder
Lord Commander Eidolon departed the 28th Expeditionary Fleet to take part in the reinforcement of the Blood Angels Legion upon the world of Urisarach, which was officially designated in Imperial records as One-Forty-Twenty, as the twentieth world to be brought into compliance by the 140th Expeditionary Fleet. This world was discovered by the 140th Expeditionary Fleet, commanded by the Blood Angels Legion's Captain Khitas Frome. Unable to translate the warnings from the orbiting Interex satellite beacons that warned approaching starships to stay away from Urisarach since it was a prison world of the sentient xenos species known as the Megarachnids, the Blood Angels Captain Khitas Frome ordered the fleet's entire contingent of three companies of Space Marines to begin landing operations to investigate and bring the planet into Imperial Compliance. Due to the extreme atmospheric turbulance, all of the Blood Angels' shuttles attempting to land on the planet became scattered and were thrown far off-course which left the Imperial landing parties isolated from each other. The atmosphere also affected Vox (radio) communications and made it difficult for the Imperial forces to coordinate their movements. Ground teams soon started sending garbled transmissions to the fleet's ships in orbit, reporting that the planet was inhabited by extremely hostile xenos.

As the reports continued, the large arachnid-like xenos were described as too numerous and formidable to defeat without reinforcements. Not long afterwards, the Blood Angels made urgent distress calls requesting immediate reinforcements and extraction. The last transmission received by the fleet came from Captain Khitas Frome himself, who noted through clenched teeth, "This. World. Is. Murder." The name stuck and became the Imperium's informal appellation for Urisarach thereafter. A company of the Emperor's Children Legion eventually arrived in response to the Blood Angels' distress calls. They made the same mistakes the Blood Angels had made, and had their landing parties scattered by the planet's powerful atmospheric disturbances. While the company took heavy casualties, one landing party led by Captain Saul Tarvitz discovered a large rock-like structure that resembled a dead tree. This "tree" had the bodies of several Blood Angels Space Marines impaled on its many branches with flying variants of the Megarachnids feasting upon the bodies. After destroying the structure, the sky above where the "tree" had been suddenly began to clear of the violent storms that had afflicted the Imperial forces from the beginning. Captain Tarvitz realized that these structures were actually artificial weather control devices that were responsible for Murder's heavy atmospheric turbulence.

The Megarchnids immediately went about rebuilding the "tree" and sent hundreds of warriors to slaughter the last few Emperor's Children remaining. There had been little honour in the initial drop to the planet’s surface, and the death and frantic nature of the combat against the loathsomely quick Megarachnid warriors. It had been brutal, intense and bloody work, and many good warriors had met their end beneath its raging, bruised skies. Thanks to Eidolon’s mistakes, there had been precious little glory won until the Luna Wolves had arrived and brought their strength to bear. Just as the Emperor's Children force were about to be overwhelmed, a relief force of newly-arrived Luna Wolves Astartes from Warmaster Horus's own 63rd Expeditionary Fleet began to land through the breach in the atmosphere. The Megarachnids were scattered and a full-scale assault on the hostile xenos of Murder began in earnest. Ten companies of Luna Wolves, the remnants of the Emperor's Children, tens of thousands of Imperial Army soldiers, and several Legio Mortis Titans proceeded to level entire swathes of the grass stalk forests and destroy every one of the "trees" they encountered, which steadily eroded Murder's atmospheric barrier. The Warmaster Horus, who was commanding the Imperial assault from his flagship in orbit, was very pleased with the progress being made. Some consideration had been paid to initiating a withdrawal from Murder now that a proper landing zone was available to allow an easy extraction of the troops, when an unexpected visitor suddenly arrived.

The Primarch Sanguinius had come to the world to inspect the dead of his original Blood Angels landing force that had been wiped out early in the campaign. Adding five of his companies of Blood Angels to the Imperial invasion force, Sanguinius and his forces fought alongside the Warmaster against the aliens. Thousands of Megarachnids poured out of the forests and canyons of Murder in an endless wave. Despite never retreating from the Imperial assault, the Megarachnids only continued to lose ground. By the sixth month of the campaign it seemed the Megarachnids would soon face extinction when the fleet deployed by the Interex arrived in-system to determine who had assaulted the Megarachnids' reservation world. Finding contact with the highly-advanced humans of the Interex to be a more pressing issue that needed to be dealt with, the Warmaster ended the campaign against the xenos of Murder.

Evolution
After another successful compliance was conducted on the Imperial designated world of Twenty-Eight Four, Eidolon underwent elective augmentative surgery under the knife of Fabius Bile. He implanted a modified tracheal implant that bonded with the Lord Commander's vocal chords, allowing him to produce a nerve paralysing shriek similar to that employed by certain warrior breeds of the Laer. When the Apothecary explained that nature of the new organ to implanted into the Lord Commander's throat, Eidolon was outraged that Bile would implant xenos filth within him. Enraged, he ordered the Apothecary to halt the surgery and release him from the medicae table. But Fabius refused the Lord Commander's orders, for Fulgrim himself had authorised his work and Eidolon had insisted that the Apothecary work on him upon his return. The Lord Commander would later make use this new ability during the Battle of Isstvan Extremis while leading his 1st Company in concert with the Death Guard Battle-Captain Nathaniel Garro and his 7th Company against traitorous forces on Istvaan Extremis, the outermost planet within the Istvaan System. Whilst fighting against a powerful Slaaneshi psyker known as a Warsinger, Garro was laid low. It was then that Eidolon took hold of the situation and employed his newly acquired abilities, destroying the Warsinger with a devastating psychic shriek. In light of this, Eidolon may potentially be considered as one of the first Noise Marines.

Eidolon's Fate
Following the Drop Site Massacre of Istvaan V, the Fulgrim and the Emperor's Children Legion are ordered to Mars by the Warmaster. But instead of following his brother's orders, the increasingly mercurial primarch decides to disobey, and instead orders his Legion to assault a Mechanicus Forge World. Unable to deal with his lord's increasingly mercurial temperament as well as his fellow senior members of the Legion, Lord Commander Eidolon questions the Primarch's orders. This proves to be a tragic miscalculation on the Lord Commander's part. Unable to placate his angered lord, the few words he managed to speak on his own behalf inadvertently provoked the Primarch further. The paranoid primarch believed that the Lord Commander was mocking him and planned to betray him. Quicker than the mind's eye could follow, the primarch withdrew his blade from its scabbard and slew his once-favoured son. Later, the severed head of the slain Eidolon was passed over the victory wine, the blood dripping from the grisly trophy and allowed to mix with the potent drink which was then shared amongst the senior members of the Legion's inner circle

Despite Eidolon's apparent death at the hands of his Primarch, Imperial authorities are still unsure as to Eidolon's current status. Indeed, official Imperial records seem to indicate that the Lord Commander was alive at least up until the Battle of Terra at the end of the Horus Heresy. Yet, rumours still persist that the Eidolon somehow survived to the modern age. Despite considerable effort, scholars in the service of the Inquisition have been unable to determine whether or not Eidolon survived the Siege of Terra. Unsubstantiated rumours claim that Eidolon has been responsible for hundreds, if not thousands, of gruesome raids on Imperial worlds in the past ten thousand years, and have suggested he may have served as lieutenant to Abaddon the Despoiler, consort to Queen Sylelle and Chaos Champion of the Daemon Prince N'Kari. Yet, no Inquisitor has yet succeeded in locating the source of these rumours, but without indisputable evidence, the Inquisition will not declare Eidolon dead.