Marius Vairosean - Great Crusade: During the Great Crusade Captain Vairosean took part in many notable actions and campaigns, which included the Cleansing of Laeran, a xenocidal campaign conducted against the serpentine alien race who called themselves the Laer.The war for Laeran was fought across many varied battlefields, the warriors of the Emperor’s Children fighting on floating atolls and through the ruins of ancient structures that reared from the oceans, while foaming breakers crashed against walls that had once stood thousands of metres in the air.During the initial assaults, Captain Vairosean fought numerous actions against Laer orbitals that had previously escaped detection, fighting boarding actions on alien vessels, controlled by Laer pilots telepathically linked to their ships in a loathsome parasitic manner.Underwater cites were discovered within days of the campaign's opening and detachments of Astartes took the fight to the abyssal darkness of undersea trenches, smashing into structures that had never known the touch of sunlight, in specially modified boarding torpedoes fired from Imperial cruisers hovering above the sea. Solomon Demeter led the 2nd Company against the first of these cities.He was present during the momentous final battle of the campaign to seize the last atoll, and his company encountered the fiercest resistance of all engaged units. On the southern spurs of the atoll, Marius Vairosean had had too many of his gunships shot down and he knew he was dangerously below the strength the primarch had decreed necessary to seize his objective.The 3rd Company had failed to reach the battlefield in accordance with the primarch's meticulous plan. Marius suffered unbearable torments at the thought that he had failed in his duty. He and his warriors were shamed, but Fulgrim forgave him, though there was nothing to forgive. Marius became sombre and withdrawn from his fellow captains, falling into a pit of self-loathing that he had dug for himself.As a result, he confined himself to the armament decks of the Pride of the Emperor , the Emperor's Children flagship, after the conquest of Laeran, mercilessly drilling his company day and night so that they would not fail again. Ever since Marius had failed Fulgrim on Laeran, he had been the most devoted servant, ever eager to please and determined to obey any order without question.Seeking any means to achieve his objectives, he willingly accepted the use of new chemical stimulants created by Chief Apothecary Fabius for testing, despite not knowing the nature of the drug or its exact origins. The primarch had authorised its use for those who wished to utilise it.Solomon Demeter was not so sure, for he did not like the idea of some new chemical being pumped into him when he did not know where it came from. He could not understand why it was needed. Marius felt that his friend's objections were irrelevant. The word had been given, and they were duty bound to obey.Their ideal of perfection and purity came from Fulgrim, and it passed down through the Lord Commanders to the Company Captains, whereupon it was beholden on them to enact the primarch's will amongst their warriors. Despite Vairosean's reassurances, to Demeter it still felt wrong.During the Laeran campaign, 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 crafted when He had created the superhuman enhancements of the Astartes was incredible, but he believed that it might be possible to go beyond what the Emperor had accomplished. Fulgrim inquired if Fabius truly believed that he could enhance the gene-seed of the Astartes.The Apothecary admitted that he did not 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 Fabius free leave to do what needed to be done. Through Fabius' ministrations, the Astartes of the Emperor's Children began undergoing surgical and chemical enhancements of their physiology.Vairosean willingly underwent these criminal and outlawed medicae surgical procedures which would eventually spread cancerously through the IIIrd Legion as the power of the Warp reached out to swallow the Emperor's Children.Chief Apothecary Fabius rewired the pleasure centres of Vairosean's brain, which resulted in the previously dour warrior becoming constantly on edge as he experienced enhanced sensations, heightened emotions and stimulation through sight, sound and touch, especially through pain.Marius initially found that through the expression of rage, he felt the most joyous of pleasures, but kept himself in check in accordance with his Legion's martial philosophy of perfection and discipline.