The bitter and twisted Chaos Space Marine Sorcerer known as Necrosius the Undying is an ancient foe of the Imperium of Man. He is a sworn servant of Nurgle, the Chaos God of pestilence, despair and decay. Necrosius is the master of the warband of Chaos Space Marines known as the Apostles of Contagion and a powerful sorcerer whose dark arts of necromancy can awaken the dead to a nightmarish half-life, unleashing the Zombie Plague of the Plague Lord upon friend and foe alike.
Necrosius was once an Apothecary of the Death Guard Legion of Space Marines during the Great Crusade whose original name has long been purged from all Imperial records. During the early days of the Horus Heresy, soon after the Death Guard turned against the Emperor of Mankind, when the Traitor Legion's fleet was becalmed in the Warp on the way to Terra and assaulted by the infectious corruption of Nurgle, the man who would become Necrosius and his fellow Apothecaries among the Astartes of the Death Guard turned their every art and skill against the strange plagues sweeping their ranks. But it was all to no avail. The decay and disease that ravaged the Death Guard was a daemonic thing of Chaos, and no mortal science or cure could hope to counter it, for the Legion had become the Chosen of Nurgle as soon as they had joined the cause of Horus. Necrosius would not stop trying to find a cure, however, and even as his fellow Astartes died around him, each in turn succumbing to despair and the macabre blessings of Nurgle's touch, he struggled on against all hope. Necrosius was obsessed with finding an answer, even as the halls of the Death Guard Strike Cruiser on which he was stationed began to unnaturally twist and corrode around him, and in the shadows daemons capered and mocked his efforts. Though his dead comrades staggered back into unholy life through the blessings of Nurgle and his own body had become a bloated and rotted husk of plague, he continued past reason and the bounds of sanity.
The Hand of Nurgle
When Necrosius heard the voice of his new lord in corruption chortling and whispering to him in the murmerous wings of carrion flies and the sibilant gurgling of rotted, decaying organs, he fully accepted the nightmare truth of what he and his fellows had been damned to become, and embraced the service of his vile God. Necrosius became a true convert to Nurgle's cause, casting aside his past learning and cherished role as a healer of his Battle-Brothers. He now chose to give himself, blighted soul and rotted body, to the lore of death and the pursuit of daemonic sorcery, and soon excelled as a master of the dark arts of necromancy. With the zealous conviction displayed only by a true convert, Necrosius quickly gathered a following among his fellows with his baleful oratory and vision of granting the "gift" of death to all Mankind. These first disciples among the corrupted Death Guard would eventually become the first members of Necrosius' new warband, the Apostles of Contagion. His bitter heart would allow him to bend the knee to no master save Grandfather Nurgle, and even his former Primarch Mortarion he obeyed only grudgingly. He long harboured a resentment of Typhus, whose betrayal had sent the once-noble Death Guard Legion to its final damnation after becoming lost in the Warp. It is a resentment that has festered into a deep rivalry and open conflict down the centuries between Necrosius' warband and the Death Guard faction led by the former First Captain of the Legion.
Apostles of Contagion
Soon Necrosius' Apostles parted company from their fellows and went their own way, spreading disease and the "gift" of the walking death wherever they went, heedless of to whom they brought their blighted contagion, whether they were servants of the Emperor or other followers of the Ruinous Powers. As a result, Necrosius and his Apostles of Contagion have made many enemies and participated in an unknown number of great atrocities through the millennia since the days of the Horus Heresy; from the horrors of the Dorisca Genocides to the blighting of the Eldar Maiden World of Cth'rawl. During these years the power of Necrosius has waxed and waned many times, and indeed sources both Imperial and from within the Forces of Chaos have believed him destroyed on numerous occassions, whether at the blades of Imperial Assassins or in the flames of Ahriman's sorcerous fires, but always he has returned. This has earned Necrosius the sobriquet "the Undying" among his devotees.
The Siege of Vraks
In 813.M41, the heretical Apostate Cardinal Xaphan of the Imperial Armoury World of Vraks Prime rebelled against the Imperium of Man. The resulting Siege of Vraks soon became a protracted military campaign fought over the course of 17 standard years to retake the rebellious world from the heretical Forces of Chaos. When Necrosius and his warband arrived on Vraks as part of the Chaos counterassault, his presence was at first unsuspected and unlooked for by ally and foe alike, as many of his enemies already believed him dead. His dark occult arts had not been seen for more than a century. Although he would accept no master, least of all the Apostate Cardinal Xaphan nor the mighty Chaos Lord Zhufor who garnered the allegiance of the bulk of the Chaos Space Marines operating on Vraks, Necrosius and his followers soon busied themselves with their own nightmarish work. The Apostles of Contagion passed among the ranks of the heretics and traitors of Vraks, spreading their bleak and unholy creed. Necrosius and his vile band of dark sorcerers performed unspeakably rites of the darkest necromancy amongst the thousands of unburied dead that littered the battlefields and mass graves of that benighted world. As the slaughter began in earnest during the Chaotic counterassault, the corpses of the fallen rose from the dead, spreading the vile corruption of the feared Zombie Plague amongst the ranks of the Imperial forces.
At the conclusion of the seventeen-year-long Imperial campaign of attrition, 34 Regiments of the Imperial Guard finally re-took the planet in 830.M41. This resulted in the deaths of 14 million Imperial Guardsmen as well as the loss of Vraks Prime's entire original population of 8 million souls which had been consumed in the violence or exterminated after they fell to the corruption of Chaos. Necrosius' whereabouts after the conclusion of the Siege of Vraks are unknown.
Prior to the Horus Heresy, Necrosius was a Space Marine Apothecary who excelled at the arts of healing. He was a dedicated practitioner of medicine and was devoted to the physical and psychological welfare of his Battle-Brothers among the Death Guard Legion until his corruption by the vile influence of the Chaos God Nurgle. Now a devotee of the Plague Lord, Necrosius is a true servant of Nurgle in body and soul, bending knee to no master save his patron God. When Necrosius and his Apostles arrive in a battle-zone, their brand of aid is always unlooked for and unwelcome among their fellow Chaotic brethren. Acting independently of whomever is in charge of these larger Chaotic forces, Necrosius and his warband spread vile disease and the necromantic Curse of Unbelief amongst both Chaotic and Imperial forces.
Weapons and Abilities
Necrosius wears corrupted Power Armour that has been marked by his patron God Nurgle. Although an incomplete set, it appears to incorporate elements of the Mark IV and Mark V patterns of Astartes Power Armour with augmetic modifications of unknown origin, including what appears to be a dangerously unstable power core venting contaminated blackish-yellow vapour. Necrosius himself appears to have partly fused with the armour as it has been damaged or burst in order to accommodate his grossly mutated form, to the point where it is impossible to know where the sorcerer ends and the armour begins. Fallen far from the glorious form of Mankind and the sacred triumph of Astartes physiology, Necrosius' body has become subjected to the warping effects of Chaos. This has manifested in horrifically bloated necrotic mutations, the swelling of the flesh and what appears to be numerous cancerous lesions and the stigmata of uncounted diseases and infections. The gifts of Nurgle such as terrible disfigurement and fatal diseases of the skin would normally cause chronic pain, but seems not to affect the followers of Nurgle in any way, and they welcome such infection as a sign of their God's favour. Despite its seemingly decayed and rotting state, Necrosius' body appears able to shrug off extremely serious injuries, with unconfirmed reports of his flesh almost instantaneously healing the damage done to it by las-fire and Bolter rounds. In addition, the sorcerer appears able to withstand any degree of ambient pollution, including the deadly toxins and gases employed by his own side without additional forms of protection.
As encountered during the Siege of Vraks, Necrosius appeared to be armed with a heavily modified Force Weapon, based or perhaps converted from an Imperial design of the kind favoured by Space Marine Librarians. The psycho-responsive metal of the Force Weapon allows a powerful psyker such as Necrosius to focus murderous energies into the blade, rendering it able to cleave through even hardened Ceramite and directly sever the life force of an individual wounded by it. Necrosius is also known to be armed with a Bolt Pistol, which he has personally adapted to fire so-called "Plague Bolts." The warheads of each bolt are converted to contain biological warfare agents, which are scattered when the bolt explodes. These are believed to be adaptations of the psyker's own invention. Like many devotees of the Plague Lord, Necrosius also employs Blight Grenades, highly effective improvised grenades made from the heads of a conquered enemy and filled with infectious blood, pus, acid and other putrid creations. The resulting missile will burst upon impact, the internal pressure throwing out the infectious liquids and gases in all directions.
Being one of the most powerful and favoured servants of Nurgle, Necrosius is attended by the tiny, impish Lesser Daemons of Nurgle known as Nurglings. These vicious creatures attack in swarms that bite and claw with infected fangs, their festering bites quickly making a minor wound turn dangerously gangrenous.
Necrosius is also adorned with the blasphemous and macabre trappings of a Chaos Sorcerer, including shrunken heads, fetishes, blasphemous glyph-carved icons and a personal banner bearing the foul symbols of Chaos, harvested body parts and the like. These totems are thought to have use in ritual practises providing a psychic focus for the sorcerer's malign psychic energies as well as fulfilling other symbolic functions. Being a powerful sorcerer, Necrosius has learned many terrible secrets from the suppurating lips of Grandfather Nurgle's daemon-kin, including the ability to raise the dead as unliving Zombie Plague.
- Imperial Armour Volume Seven - The Siege of Vraks - Part Three, pp. 14-15, 143