Eidolon - Cleansing of Laeran: Shortly after the beginning of their own Crusade, the Emperor`s Children encountered a hitherto-unknown alien race upon the Xenos World called Laeran, officially designated as Twenty-Eight Three, being the third world the 28th Expedition had brought to Imperial Compliance.Unbeknownst to the IIIrd 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 stars and had made it abundantly clear that they held the Imperium in nothing but contempt. The IIIrd 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 IIIrd Legion's Chief Apothecary Fabius 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, Fabius 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, but what if it was but the first step on a longer road?Fabius 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 if Fabius 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. Fulgrim agreed with the Apothecary's proposition and gave Fabius free leave to do what needed to be done.With the end of the campaign on Laeran, the steady stream of wounded and dead to the Apothecarion 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 Fabius'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, Fabius would begin his experimentation on him. Through the Apothecary's genetic enhancements, the Lord Commander hoped to become Fabius's greatest success, faster, and more deadly then ever before. He wished to become the indispensable right hand of the Primarch.