Halo Devices are xenos artefacts discovered amidst the ruins of ancient alien worlds in the Halo Stars. The devices use a process completely beyond the understanding of Imperial lore to manipulate the body and mind of those they bond with, making their hosts extremely difficult to kill and effectively immortal. However, the price paid is madness, loss of humanity, and strange thirsts and addictions such as the need to consume blood and flesh.
The worlds from which Halo Devices are found are truly ancient and utterly lifeless, orbiting dead stars that must have burned their brightest many thousands of millennia ago. They are usually found buried in the decayed basalt biers and shattered cyclopean ruins of their maker’s civilization. That such worlds were once part of some long dead civilization, believed to predate even the Eldar, is generally agreed upon by xeno-arcanists and Rogue Traders, but just what the creatures from this civilization were or how they passed into extinction is a question that has never been answered.
Possessed of strange and potent properties, Halo Devices can fetch high prices within the Imperium where collectors covet their ability to empower the human form and defeat even mortality itself. Possession of such dangerous xeno archeotech is highly heretical. The devices have been condemned by both the Ordo Xenos and the Adeptus Mechanicus, and the lives of those in possession of a Halo Device are forfeit within the Imperium. Even with all the risk involved, there is a secret trade in such items to corrupt members of the elite and the wealthy of the Imperium. Knowing the risks of the devices, the Inquisition has watched the sectors around the Halo Stars for any sign of those who trade in them for centuries.
Congregations of Inquisitors have been created and have even died in the war against these malign objects from the Halo Stars' past. There are dedicated cells of Acolytes who have spent their entire careers researching and hunting down the devices, those who traffic in their trade and those corrupt souls who would use them. Despite these aggressive countermeasures by the Inquisition, tales of the wondrous devices that grant immortality continue to circulate in the decadent circles of the wealthy elite. Though most of these tales are false, these rumours have the power to attract the foolish to pursue such devices down paths that lead them to heresy.
Those few who seek Halo Devices have a simple but terrible motivation for their desire—the youth and eternal vigour bestowed by them. Rejuvenat treatments, sanguinary cleansing, and other techno-biological rituals can only preserve life only so far. Even extreme solutions to aging such as full augmetic conversion and life support offer at best a pale imitation of life. Those desperate enough to desire a true freedom from the cruel touch of time seek a more permanent measure. For some, the Ruinous Powers await with their own lies and empty promises. However, this path is as uncertain as it is filled with danger to both one's body and soul. Others, rich, ruthless, and sufficiently well connected, use their resources to turn to the half-rumoured mysteries of the alien Halo Devices for salvation.
Halo Devices come in many forms and appear to be untouched by the effects of time. Most are small and easily confused with odd jewellery, small pieces of armour, and curious miniature statuary. Some range in appearance from smooth, carbuncular talismans to strange scarab or fossil-like objects, or sinister orbs with fluid and glossy surfaces. The form of a Halo Device is known to have no influence over its powers. Whichever their shape they all seem to be made from a strange metallic material that defies analysis by auspices or scanners, and are nearly impervious to harm. A curious trait that all the devices share is that they will not bond with anyone who worships Chaos, is possessed, or a psyker. A Halo Device seems to want nothing to influence the user but itself.
Halo Devices require the flesh of a host, and if kept in contact with flesh, they will bond with it and, over time, change that flesh to suit their purposes. This process of change moves through three phases: primary, secondary, and tertiary. Once a person is into the primary phase there is no turning back, and they will eventually pass to the secondary and tertiary phases unless they are destroyed. The life of a possessor of a Halo Device becomes less their own and more that of the device itself.
Once bonded with the device, the user rejuvenates so that they are in the peak of their youth and health. Any physical diseases, deformities, minor mutations, or other long-term medical conditions that they were suffering from are negated. Any part of the user's body that has been lost re-grows during this phase (albeit slowly and painfully), their senses become superbly attuned, they move with an unnatural grace, and they shrug off all but the most grievous wounds. Even as their body changes, the user's mind has begun to slowly crumble and one by one the pleasures they had in life, begin to lose their luster. Paranoia and violent mood swings set in and they begin to hear strange voices that whisper to them in the dark. As time progresses, they learn that they no longer require sleep, except for a few comatose hours every few days during which they suffer vivid nightmares of alien vistas and strange cities beneath mysterious stars.
Years later, the area where the device was bonded to the flesh begins to change, becoming mottled and tough like the exoskeleton of an insect or becoming desiccated and cold like that of an embalmed corpse. The body of the user heals almost any damage and is inhumanly fast, strong, and resilient. They no longer sleep, eat, or drink normal sustenance, but as they slip further into madness, they develop strange addictions and insatiable hungers that they must regularly indulge or grow increasingly unstable and sickly. These addictions often include spending long periods in total darkness or complete immersion in solar radiation, and the hungers are often for substances like human flesh.
The user also finds that they have memories of strange alien civilizations, languages, and scripts meshing with their own and may lose large chunks of their own memories. If the user is killed during this period and their body is not destroyed (burned to ash, dismembered, etc.) and the Halo Device is still attached to their corpse, there is a chance that their body will repair itself and re-animate. This resurrection drives the user irrevocably insane, and they immediately progress to the tertiary phase.
After decades of contact or resurrection, there is no longer any separation between the user and the Halo Device whatsoever; their bodies become permanently altered, remaining humanoid but no longer human. Instances of burning, radiant eyes, corpse-like flesh, distorted gaunt features, mottled or armoured hide-like skin, and even a fine beetle-like carapace are all recorded, and almost invariably the fingers of the hands transform into long talons of exposed bone, as the body grows more alien and grotesque. The personality and identity of the user is completely destroyed and in its place is an ancient and alien intelligence. The thing that was once human is now so strong it can rip a man's head from his shoulders with casual ease, survive the touch of the void, and even return from death.
If the user is killed, but their body is not destroyed, it reanimates in a matter of days and awakens with an insatiable hunger. Though dismissed by many in the Ordo Xenos, ancient tales of the devices state that even if the body of a user is rendered down to mangled bones or burned to ash, should the remains be immersed in human blood and flesh and exposed to high electrical current or radiation, there is a chance it will be resurrected, reforming in minutes from a maelstrom of blood and unnatural energies.
Known Halo Devices