A Tech-thrall, also known as an Adsecularis when used for military purposes, was a cybernetic servant created by the Mechanicum during the Great Crusade and Horus Heresy era. These cyborgs were created as the need for them arose by replacing portions of the subject's organic anatomy, central nervous system and physiology with basic augmetics. In the case of the Legio Cybernetica Tech-thralls were commonly created from captured prisoners and criminals requisitioned from local authorities. Considered a lower order of being than even Servitors by their masters, the ultimate fate of most Tech-thralls was to end their lives recycled into Servitor components and their implants harvested for use in future thralls as their bodies failed under the relentless toil to which they were subjected. In times of war, Tech-thralls were formed into expendable units called Adsecularis and armed with basic weapon systems such as the Mitralock, a compact multi-chambered variant of the Las-lock, designed to discharge a simultaneous volley of laser pulses in a fan effect. It is not known if this type of cyborg servant is still present within the ranks of the Adeptus Mechanicus in the late 41st Millennium.
Tech-thralls were specialised troops of the Legio Cybernetica created by the Mechanicum through basic augmetics and cranial surgery as the need for them arose, especially during the massive Imperial expansion during the Great Crusade and later the interstellar civil war known as the Horus Heresy. They were not Servitors, which used often formerly human biological matter as a component system, but rather could be considered cyborgs as consciousness and memory was not extinguished before they were reprocessed into their new forms, merely mutilated and overridden. The conversion process commonly awaited the laity of a Forge World's population should it prove sub-standard or commit some transgression against its masters, for few other criminal punishments existed in the Omnissiah's domains. Tech-thralls served many purposes, but principally that of a flexible pool of expendable labour on the Forge Worlds. But in times of war, this same fate befell many to create a quickly produced and ultimately expendable military resource known as the Adsecularis. In these cases, the organic human bodies of the Tech-thralls, already altered to lift heavy loads, functioned in hostile environments and obeyed the orders of their masters until death. Tech-thralls were fitted with basic weapons systems and bodily protection. On the battlefield they served as expendable troops, unskilled but relentless and indefatigable; an army of the alive-yet-dead, puppeted by the Mechanicum Magi who commanded them.
- Flak Armour - Flak Armour is a light and relatively simple form of body armour used by the military forces of the Imperium of Man. It is used as standard issue body armour for the countless millions of Imperial Guardsmen and Planetary Defence Force members across the galaxy. Many layers of ablative and impact absorbent material go into making each suit, enough to deflect or negate most low-level attacks such as small arms, shrapnel, and proximity blasts. Solid hits from high impact weapons can generally negate it, but given that it is relatively lightweight, cheap to produce, and dependable in most combat situations, many veterans keep using Flak Armour even when offered better. A Flak Armour set usually consists of a breastplate, shoulder pauldrons, knee plates, greaves and a helmet.
- Las-lock - A somewhat archaic alternative to the mass-produced lascarbines favoured by many regiments and war hosts of the Imperial Army, Las-locks were shoulder arms whose design favoured stopping power over rate of fire or range. Mitra-locks were a compact, multi-chambered variant of the Las-lock, designed to discharge a simultaneous volley of las-pulses in a fan effect at short range that was akin to a shotgun blast.
- Heavy Chainsword (or other Close Combat Weapon) - The Chainsword is the preferred close combat melee weapon of many of the military forces of the Imperium of Man. The Chainsword is essentially a sword with powered teeth that run along a single-edged blade like that of a chainsaw. Most versions of the weapon make use of monomolecularly-edged or otherwise razor-sharp teeth. Chainswords are not subtle weapons, and wielding one is a statement in its own right: they are horrific tools of war, designed to bite, tear and eviscerate where more primitive blades merely cut and slice. The weapon makes an angry buzzing sound as the teeth spin around, intensifying into a high pitched scream as they grind into armour. It is not unlike a modern chainsaw, but lighter and able to be wielded with one hand.
- The Rite of Pure Thought - A squad of Tech-thralls with this upgrade has undergone massive cranial surgery to destroy the emotional and instinctual responses centres of the human brain.
- Revenant Alchemistery - Certain Forge Worlds, particularly those far from the direct oversight of Mars, were commonly held to contain elements which practiced the forbidden arts of the Dark Age of Technology. Rumours of the use of the forbidden Sarcosa Wave and Black Alchemistry were rare before the war of the Horus Heresy, but as anarchy and bloodshed erupted on a galactic scale, some Taghmata on both sides of the divide of Traitor and Loyalist were accused of fielding Tech-thralls animated from the battlefield dead using such terrible and prohibited knowledge.
- The Horus Heresy - Book Three: Extermination (Forge World Series) by Alan Bligh, pg. 221
- Forge World - Tech-Thralls with Mitralocks