Necrosius

The bitter and twisted sorcerer known as Necrosius is an ancient foe of the Imperium. A sworn servant of Nurgle, the Chaos God of pestilence, despair and decay. Necrosius is the master of the Plague God-devoted warband known as the Apostles of Contagion and a powerful sorcerer whose dark arts can awaken the dead to a nightmarish half-life.

History
Necrosius was once an Apothecary of the Death Guard Legion whose true name has long been purged from all records. During the dark days of the Horus Heresey, when the Legion's fleet was becalmed in the Warp and invaded by corruption of Nurgle, the man who would become Necrosius and his fellows turned their every art and skill against the plagues sweeping their ranks but it was to no avail. The decay and disease that ravaged the Death Guard was a thing of Chaos, no mortal science or cure could hope to counter and the Legion had been betrayed to its damnation in suffering at Nurgle's hands. Necrosius would not stop trying however, and even as his fellow Astartes died around him, succumbing each in turn to despair and the macabre blessings of Nurgle's touch, he struggled on against all hope, obsessed with finding an answer, even though the halls of the 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 and his own body had become a bloated and rotted husk, he continued past reason and past the bounds of sanity.

The Hand of Nurgle
When Necrosius heard the voice of his new father in corruption chortling and whispering to him in the murmerous wings of carrion flies and the sibilant gurgling of rotted, decaying organs, he full embraced 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 and gave himself, blighted soul and rotted body to the lore of death and the pursuit of Daemonic sorcery, excelling as a master of the dark arts. With the zealous conviction of 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 Apostles of Contagion. His bitter heart would allow him to bend the knee to no master save Father Nurgle, even his former lord Mortarion he obeyed only grudgingly and long has he harboured a resentment of Typhus, whose betrayal sent the once-noble Death Guard Legion to its final damnation. It is a resentment that has festered into a hateful rivalry and open conflict down the centuries between his faction and that of the former Death Guard Captain.

Apostles of Corruption
Soon Necrosius' Apostles parted company from their fellows and went their own way, spreading disease and walking death wherever they went, heedless to whom they brought their blighted 'gifts' be they servants of the Emperor or followers of the Ruinous Powers. As a result he and his Apostles of Contagion have made many enemies and participated in an unknown number of great atrocities down 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 many years the power of Necrosius has waxed and waned many times, and indeed sources both Imperial and 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, earning him 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 Mankind. The Siege of Vraks soon became a protracted military campaign fought over the course of seventeen 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 counter-assault, his presence was at first unsuspected and unlooked for by ally and foe alike, as many of his enemies 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 heretic Cardinal Xaphan nor indeed the mighty Lord Zhuphor who garnered the allegiance of the bulk of the Chaos Space Marines on Vraks, Necrosius and his followers soon busied themselves with their own nightmarish work. The Apostles of Contagion passed among the ranks of the renegades of Vraks, spreading their bleak and unholy creed. Necrosius and his vile band of dark sorcerers performed unspeakably rites of the darkest sorcery amongst the thousands of unburied dead that littered the battlefields and mass graves. As the slaughter began in earnest by Chaos counter-assault, the corpses of the fallen rose from the dead, spreading their vile corruption amongst the ranks of the Imperial forces.

At the conclusion of the seventeen year long Imperial campaign of attrition, thirty four Regiments of the Imperial Guard finally re-took the planet in 830.M41. This resulted in the deaths of fourteen million Imperial Guardsmen as well as the loss of Vraks Prime's entire original population of eight million souls which had been consumed in the violence or exterminated after they fell corruption of Chaos. Necrosius' whereabouts after the conclusion of the Siege of Vraks are unknown.

Characterisation
Prior to the Horus Heresy, Necrosius was an Apothecary whom excelled at the arts of healing. He was a dedicated practitioner of medicine and the physical welfare of his battle-brothers until his corruption to the vile influence of the Chaos God Nurgle. Now a devotee of the Plague God, Necrosius is a true devout follower of the Lord of Plagues, bending knee to no master save his patron god. When Necrosius and his Apostles arrive in a battle-zone, their aid is unlooked for by their fellow Chaos brethren. Acting independently of whomever is in charge of these large Chaos forces, Necrosius and his warband acts independently, spreading vile disease and walking death amongst both Chaos and Imperial forces.

Weapons and Abilities
Necrosius wears corrupted Power Armour marked by his patron god Nurgle. Although incomplete it appears to incorporate elements of MK IV and MK V 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 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 the Adeptus Astartes physiology, Necrosius' body has become subjected to the warping effects of Chaos. This has manifested in horrifically bloated necrotic mutations, swelling of the flesh and what appears to be numerous cancerous lesions and the stigmata of uncounted diseases and infections. The gifts of Nurgle; disfigurement and contamination of diseases of the skin would normally cause chronic pain, but seems not to affect the followers of Nurgle in any way. 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 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 psyker such as Necrosius to focus murderous energies into the blade, rendering it able to cleave through even hardened ceremite 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 '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 Nurgle, 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 which 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 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 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 energies as well as fulfilling other symbolic functions. Being a powerful sorcerer, Necrosius has learned many terrible secrets from the suppurating lips of Father Nurgle's daemon-kin, including the ability to raise the dead as unliving Plague Zombies.