Lost and Forbidden Technologies of the Legiones Astartes

 Lost and Forbidden Technologies of the Legiones Astartes

 

Introduction 

 

Much has been written about all the many achievements of the Great Crusade, the magnificent fleets, glorious monuments, great battles and the mighty heroes who won them. Yet the uglier aspects of the Great Crusade are often overlooked or intentionally erased. Civilizations annihilated, vast archives of history and culture burned, species rendered extinct and whole worlds wiped clean of life. The Great Crusade saw weapons unleashed on the galaxy that had not been used since the start of Old Night and the collapse of the ancient human galactic civilization. Many of the worst of these weapons were commonplace on Terra before the Emperor launched his Unification Wars, genetically modified killing machines, archaeotech weapons of unbelievable destructive power, rad-weapons, genophages, warp and temporal distorting weapons, the nightmares of Old Night were truly beyond the comprehension of most mortal men. In his wisdom the Emperor locked most of these terrible horrors in the vaults beneath his palace and seat of power atop the Himalayan mountains, a fortress that would in time come to be known as the Emperor's Palace. However select weapons and technologies were entrusted into the care of the Legiones Astartes. Some of these weapons could be found in the armories of every legion in some number while others were unique to only one of the space marine legions. Some of these technologies will be explained here and now. 

Accelerator Autocannon

 

Modern autocannons are a far cry from the advanced weaponry available to the Legiones Astartes during the Great Crusade. The most impressive of which were the twin accelerator cannons used as the standard armament for the Sicaran battle-tank. Using magnetic acceleration technology to increase the velocity of the autocannon shells to extreme speeds the accelerator autocannons were capable of delivering armor penetrating rounds accurately against their targets in rapid succession. Mounted on the highly mobile, well armored and machine-spirit guided platform of the advanced Sicaran battle tanks the accelerator autocannons made for fearsome tank hunting guns despite the relative weakness of each individual shot. In the wake of the Horus Heresy many of the more technologically advanced and sophisticated warmachines used by the space marine legions fell out of use, either too resource demanding to create or difficult to maintain to continue their deployment or the knowledge of their creation having been lost entirely. The Sicaran battle-tank and it's signature autocannons were among those casualties. Today only a handful of these relic machines remain in the armories of the oldest space marine chapters. 

 

Advanced Power and Terminator Armors

 

The first power armor deployed by the Emperor's warriors, the Thunder Armor, was a pitiful shadow of the advanced armors that would clad the warriors of the legiones astartes at the height of the Great Crusade. Thunder armor was not environmentally sealed or provided any kind of life-support, it only provided powered assistance to the upper body and did not even feature a fully enclosed helmet. The first true power armor fielded by the space marines was the MKII Crusade armor that finally fully enclosed the wearer in powered armor plates, was void-sealed and featured an inbuilt air-supply, magnetic boots and visual enhancement. MKII armor was a massive leap forward and would continue to be used in some capacity throughout the Great Crusade and even the Horus Heresy but demand for more and better armor would quickly see the Mechanicum iterate further on the design. The up-armored MKIII Iron Armor followed but it was really just additional frontal armor plates bolted onto the older MKII design. It wasn't until the deployment of the MKIV Maximus armor that power armor truly reached it's apex. The MKIV featured a more advanced respirator design sloped to provide better facial protection while still maintaining hardened environment seals, a reinforced collar, a chestplate that sloped down to cover the lower abdomen, better articulated knee and elbow plates as well as extended vambraces that protected hands and wrist from hyper-extension as well as the use of more advanced composites made the MKIV truly a wonder of technology. However the advancements of MKIV meant that the armor was much more time and resource intensive to produce and only some legions were able to field their warriors in such armor in mass while many legions, especially those with higher attrition rates or poorer supply chains, were forced to rely on older marks of armor. The Horus Heresy would see armor stocks rapidly depleted and the legions were forced to implement MKV Heresy armor, effectively a catch all for a wide variety of field repairs and augmentations that produced functional, if vastly inferior powered armor. The wide-scale deployment of MKVI would produce an armor that was much more modular and more easily maintained but again less advanced than the MKIV had been. However power armor was not the only armor the Mechanicum had been developing prior to the Horus Heresy. 

Terminator Armor, otherwise known as Tactical Dreadnought Armor also saw widescale development and the deployment of several different iterations. The earliest Saturnine armor were relics recovered in the Unification wars and the conquest of Sol but fell quickly out of use in favor of the Cataphractii, Indomitus and Tartaros armors. The Tartaros Terminator Armor in particular was essentially an up-armored variant of the MKIV Maximus power armor and was generally considered the peak of personal protection developed during the Great Crusade. It is widely speculated that terminator armor was ultimately meant to replace power armor as the standard armor of the legiones astartes when the Mechanicum could reach a scale of production necessary to meet the demands of the legiones astartes. Even without managing such mass scale production the Imperium still managed to produce many thousands of suits of Terminator armor of a number of varieties and some legions even developed their own unique variants such as the Gorgon-pattern developed by the Primarch Ferrus Manus. Nevertheless the fires of the Horus Heresy would severely negatively impact the Imperium's ability to produce highly advanced technology, especially on a mass scale. Cataphractii and Tartaros terminator armor would become effectively irreplaceable and even the less sophisticated Indomitus armor would become extremely rare and difficult to produce or maintain. MKIV armor would vanish from the armories of the space marines almost entirely, becoming rare pieces of relic plate mixed in with later marks of armor as chapters equipped their warriors with whatever they could find or produce themselves.  

 

Alchem-Munitions

A blanket term for a wide variety of different chemical weaponry, alchem weapons were rarely employed by the Legiones Astartes save for the sole exception of the Death Guard. Following the lead of their poison breathing primarch Mortarion the Death Guard utilized an array of different dispersal methods for all manner of toxic, corrosive, poisonous and viral compounds. The dreadful Grave Warden terminators of the Death Guard carried as standard heavy grenade launchers loaded with poisonous gas grenades and squads may be further augmented with customized heavy flamers that replace the standard prometheum mixture with alchemical liquids of different types. Deathshroud terminators, the exclusive bodyguards and enforcers of Mortarion himself, also carried wrist-mounted grenade launchers equipped with gas grenades. Rather than restricting alchem-weapons to specialist Destroyer squads any unit of the Death Guard could potentially be equipped with alchem-flamers, grenade or missile launchers. No other legion employed alchem-weapons in anything like the numbers or frequency of the Death Guard, if they possessed such weapons in their arsenals at all. 

Archaeotech Pistols

Archaeotech is a catch-all term for any technology that is of ancient human origin and that the Mechanicum neither understands the function of or possesses the capability to reproduce. In the Great Crusade a wide variety of archaeotech weapons found their way into the hands of the Emperor's warriors from the Kinetic Destroyers used by the Custodes assault specialists to the mysterious Lantern sidearm carried by the primarch Mortarion. Most of these weapons took the form of handheld sidearms of various function but usually appearing as some kind of mechanical revolvers. In actuality these firearms could be everything from devastating energy weapons to more rudimentary weapons that fired highly specialized and deadly ammunition. While extremely rare these weapons were still common enough to be found in the armories of every legion and could even be seen in the hands of solar auxilia commanders and rogue traders militant. Regardless of their shape, size or function archaeotech pistols are universally extremely powerful and deadly, capable of cutting through power armor, energy shields and reinforced chitin hide with equal ease and causing devastating damage to organic and mechanical materials alike. While all the armaments carried by the primarchs bore names and reputations of renown many were archaeotech pistols of some kind, forged long before the Unification Wars. Like many artifacts of a rare and priceless nature countless archaeotech pistols were lost in the fires of the Horus Heresy. No examples of such weapons remain in the armories of the modern space marine chapters and only a handful have ever been seen on the battlefields of the forty-second millennium. One such weapon has been spotted in the possession of the freeblade knight scion Sir Hekhtur, while the Adeptus Mechanicus still fields small numbers of weapons that technically fall into this category such as phosphor serpentas and gamma pistols. 

Armatus Necrotechnika

These forbidden archaeotech devices were locked away in the personal vaults of the Primarch Ferrus Manus on his homeworld of Medusa. Following the Istvaan V Dropsite Massacre elements of the surviving Iron Hands legion opened the vaults and unleashed these fell devices. Capable of harnessing life energy to repair and reanimate machines the Iron Hands used them to create nearly immortal cyborg soldiers. The already heavily augmented Iron Hands physiology merged with the Armatus Necrotechnika to create undying warriors capable of being reanimated and returned to the battlefield time and time again. Given that the Iron Hands were not present on Terra during the siege or part of the relief forces that arrived afterwards it is unclear whether other loyalist forces ever witnessed the Armatus Necrotechnika in action or had the opportunity to question the Iron Hands about the devices. In the aftermath of the Heresy the Iron Hands appear to have sealed these forbidden heretek devices away and it is unknown if the chapter has ever used them again. 

Atomantic Reactors

Atomantic Arc-Reactors were one of the most essential technological rediscoveries during the early days of the Great Crusade. These powerful, if temperamental and difficult to maintain, devices functioned as extremely powerful and compact power sources capable of meeting the extremely high energy requirements of the more advanced warmachines used by the Legiones Astartes. Contemptor and Leviathan Dreadnoughts, super-heavy tanks like the Glaive and Fellblade, the Cerberus heavy tank destroyer and many other warmachines would not have been capable of functioning without such an advanced and powerful generator at their heart and in some cases they pushed the limits of even atomantic reactors to the extreme. Despite the best efforts of the Adeptus Mechanicus the glorious atomantic reactors were one of the many casualties of the Horus Heresy. Today such devices can only be found in a handful of the warmachines still fielded by the adeptus Mechanicus or within the armored hulls of relic warmachines found in the armories of the oldest and most fortunate chapters. Without such powerful reactors many machines and weapons fell out of use by the adeptus astartes. Perhaps most notably the more advanced dreadnought chassis such as the Contemptor, Deredeo and Leviathan could not be maintained without these reactors and the inbuilt deflector shields these dreadnoughts benefited from are absent from the later castaferrum dreadnoughts common among the later firstborn chapters or even the newly forged Redemptor dreadnoughts of the Primaris chapters. Even the Astraeus super-heavy grav tanks of the Primaris are protected by void shield generators rather than the more sophisticated atomantic-reactor powered defense screens. 

Charnabal Sabres

The term charnabal sabre refers to a wide variety of masterwork swords forged across the surface of Terra and used in the many wars of conquest and domination fought during the age of strife. Forged in many different styles and forms by ancient clans of master craftsman to supply the needs of noble duelists, assassin clans and death cults alike. Regardless of their form or the particular technique of forging these weapons are widely regarded as among the finest examples of bladed weapons in the galaxy and much prized by the officers and champions of a number of legions and especially by the master swordsman of the Emperor's Children. What especially sets the charnabal sabres apart from the more common weapons of the legiones astartes is that they generally do not incorporate a disruptor field generator and are not powered weapons. Inbuilt power field generators are capable of turning almost any blade into a weapon of extreme danger capable of shearing through nearly any physical protection with contemptuous ease. However the charnabal sabres did not need such improvements to perform with superb lethality on the battlefield. Whether the result of some ancient secret forging technique or some extremely rare and difficult to forge material the blades of charnabal sabres were so magnificent they were capable of clashing with the disruptor fields of power weapons without suffering damage and could cut through almost any armored protection without difficulty. It is unclear whether the wars of unity managed to secure Terra without the destruction of all of the master craftsman capable of forging such weapons but even if some such blades were still being produced on Terra after unity the widespread annihilation wrought on the throneworld by the Horus Heresy almost certainly put an end to the continued creation of such masterwork swords. Whole hives burned or were turned into gas chocked carnal houses, collapsed by tectonic shifts or pounded flat by orbital bombardments and took populations of billions with them. No secret forge or hidden swordsmith clan stronghold could survive such wholesale slaughter and destruction and in the years after the Horus Heresy these legendary blades appear to have vanished from the armories of the adeptus astartes. Even among the remnants of the traitor III legion these once prized weapons appear to have been long ago replaced by more common powered sabres. 

Disintegrators

Of all the weapons prized by the warlords of Terra during the age of strife the disintegrators were among the most fiercely contested. Caches of even a handful of these powerful energy weapons could see entire armies tearing each other apart and those commanders who were able to field these weapons in any numbers enjoyed a powerful advantage over almost any opponent. The energy beam projected by disintegrator weaponry literally breaks apart the target at the molecular level, obliterating flesh and armor alike into a cloud of filthy smoke. Not only extremely powerful the psychological impact of disintegrator weapons was extreme, for an enemy to see their most prized warriors transformed into ashe in moments could turn the fiercest of hearts to despair and put whole armies to route. The Emperor was diligent in securing surviving caches of disintegrator weapons quickly and they were a staple in the armories of the Thunder legions and the early Legiones Astartes. The most powerful disintegrator weapons, known as Adrathic disintegrators, were completely forbidden for anyone but the Imperial household to possess and failing to turn over even a single example of such a weapon could lead to annihilation. Despite their power disintegrator weapons were also highly unstable and dangerous to their wielders, often backfiring to lethal effect or malfunctioning explosively. The technology of such weapons was poorly understood even at the height of the Great Crusade and as such these weapons fell out of favor among most legions in favor of the more stable and reliable volkite weaponry. However many legions did maintain a number of these powerful weapons in their armories up through the end of the Great Crusade and they saw a resurgence in the terrible wars of the Horus Heresy. From the killing fields of Istvaan V to the siege of Terra itself the legions turned to the most wicked and powerful weapons in their arsenals to wage war against their former brothers and that included disintegrators. The naive reintroduction to all legions of Saturnine terminator armor and dreadnoughts by Vulkan also brought a resurgence of disintegrator weapons as these energy hungry weapons were ably supplied by the advanced reactors of those warsuits and made for powerful weapons in conflicts between legions. Although many thousands of these weapons could be found in the armories of the legiones astartes during the Great Crusade and Horus Heresy they are yet another technological casualty of the bitter civil war that set the galaxy aflame and in the centuries that followed the siege of Terra the disintegrator fell out of use among the chapters of the adeptus astartes and is completely absent from the armories of the modern chapters and even the genius of Archmagos Dominus Bellisarius Cawl has yet to unlock the secrets of these ancient and powerful weapons. 

Escaton Power Claws

Based on examples of archaeotech recovered from the war ravaged world of Elemghast the Escaton power claws combined the mass-acceleration effect of power fists with the disruptor-field shrouded blades of lightning claws. The result were weapons that could punch through the heaviest armor with ease as well as rip and tear through armor and flesh with incredible speed and brutality. Although still generally prototype weaponry the first production-grade examples of these weapons were routed by Horus into the hands of the Sons of Horus and Night Lords and are otherwise almost completely absent from the armories of every other legion save those claimed as trophies from the corpses of their former wielders. In particular the Contekar terminator elite of the Night Lords prized these weapons as their primary armament and the bulk of such weapons that made it to the Night Lords were reserved for these brutal enforcers of the first company. In the wake of the Horus Heresy it is unclear if any examples of these weapons survived but if so they have not been seen even among the ranks of the traitor legions in the centuries since, perhaps for the better. 

Flare Shields

Flare shields, technically known as electromagnetic flux field generators, are a potent defensive screen widely deployed by the armies of the Imperium during the Great Crusade and the Horus Heresy. Most vehicles employed by the Legiones Astartes, Mechanicum and even the Solar Auxilia and Imperial army could be upgraded with these devices if their commanders possessed the resources and wherewithal to do so. Not defensive power fields in the basic sense flare shields instead acted to slow and weaken incoming enemy weapons fire from the frontal arc, transferring some of the ballistic and energy impact of attacks into flashes of light. Although flare shields did not stop incoming fire entirely like atomantic defense screens or power field generators they did weaken shots significantly allowing for the heavy frontal armor of various battle tanks and warmachines to better absorb and shrug off hits. Even select examples of knight armors deployed by the Mechanicum were upgraded to employ ionic flare shields, defensive barriers incorporating both ion shields and flare shields into their function while the heaviest warmachines of the legiones astartes would often utilize flare shields to enable them to surge into the thick of the heaviest fighting. Like all too many advanced technologies flare shields were lost to the Imperium after the destruction of the Horus Heresy and are entirely absent from the battlefields of the forty-second millennium. 

Legio Cybernetica Cohorts

Normally reserved for the exclusive use of the Mechanicum Taghmata the battle-automata of the Martian priesthood were occasionally seconded to the Legiones Astartes and commanded in battle by highly-trained specialists known as Legion Praevians. Inducted into the rites and rituals of cybertheurgy the Praevian was able to command the extremely powerful battle robots of the Mechanicum in combat alongside their legion brothers. From the fast and deadly Ursarax to the Thanatar siege automata these machines were extraordinarily powerful but also temperamental and challenging to effectively utilize. True abominable intelligence were long forbidden by humanity, instead the automata of the Mechanicum were built around the still-living brains of human subjects implanted within the armored frames of the automata and shackled to ritualized binharic programming. Some of the subjects used in the creation of Legio Cybernetica machines were willing, some were not, all live a ghoulish half-existence, their minds critical to the function of these battle robots but their free will and identity overridden by the Tech Priests of Mars who created them. Despite this distinction the limited autonomy of the Legio Cybernetica would ultimately lead to the ban of this technology, the modern Mechanicus relies exclusively on Castellan Robots, machines driven by pre-programmed data wafers without a conscious mind of any kind operating within their armored frames. Some legions utilized automata more than others, the Thousand Sons built their own Castellax-Achea machines while the Iron Warriors primarch Perturabo would ultimately replace his personal guardians with his own hand-built Domitar-Ferrum robots. Even the modern Thousand Sons still use a form of combat automata known as Sekhetar robots. Rumors persist, though heavily denied by the Mechanicus and the Iron Hands, that the sons of Ferrus Manus most ancient and elite warriors the Hellfathers, may have completely replaced all traces of their biological flesh including their brains and become completely mechanical. Such a thing would be tech-heresy of the highest form and is almost certainly untrue, nevertheless the rumors persist. 

Men of Iron

Built by mankind as servants and soldiers in the golden age before the fall of Old Night the Men of Iron were autonomous artificial intelligence machines that took a wide variety of forms and served in many different capacities. It is little known that the core of every standard template construct or STC machine was an artificial intelligence. How, when or why the Men of Iron rebelled against their masters has been lost to time, what is known is that the war between humanity and their artificial servants was unimaginably destructive and led to the loss of countless planets and trillions of lives. In the aftermath humanity forbade the creation or use of self-aware machine minds, now known as abominable intelligence. Unknown to the rest of the Imperium the Emperor captured a handful of these terrible minds during the Unification Wars and gave them into the care of his first legion, the Dark Angels. Held within vaults deep in the heart of the Invincible Reason a handful of Men of Iron were shackled by impenetrable binharic command codes, their twisted minds broken beyond all comprehension and entombed in imperial battle robot bodies. In the most dire of circumstances the primarch Lion El'Johnson could employ these terrible monstrosities of Old Night as devastating shock troops of incredible and nightmarish power. Whether any of these horrors remains in the possession of the modern Dark Angels is unknown. 

Neutron-Lasers

Devastatingly powerful directed energy weapons, Neutron-lasers are second to none in terms of armor-killing firepower for their size. Neutron lasers fire a beam of energy capable of rupturing enemy armor at a molecular level, even should the target withstand the initial impact Neutron lasers also direct a powerful electro-magnetic pulse along the beam, frying most electrical systems not specially shielded against such hazards. In current day only the Mechanicus fields such weaponry in limited numbers mounted on their Dunecrawler battle-tanks but during the Great Crusade the Legiones Astartes fielded many such weapons on a wide variety of different armored vehicles. Sabre strike-tanks could be equipped with short barreled Neutron-blasters while the fast and deadly Sicaran-venator mounted a large Neutron beam laser within it's armored hull and the mighty Cerberus heavy tank destroyer's primary weapon was a trio of heavy Neutron lasers. While exceptionally powerful Neutron lasers are difficult to maintain and require immense power to function. In the modern day the Mechanicus utilize a more stable neutronic coil arc-reactor in the Onager Dunecrawler tanks but in the Great Crusade the Mechanicum relied on unstable and volatile atomantic arc-reactors. Should the weapons suffer critical damage the atomantic reactors could detonate with enormous force. More problematic should the Neutron laser beam fail to fully discharge the electro-magnetic energy of it's firing into the target the energy can feedback into the weapon and damage it and the carrying vehicle. In the aftermath of the Horus Heresy these powerful but temperamental weapons fell out of use by the loyalist space marines and today only the most fortunate or ancient of chapters possess any examples of such weapons in their armories. 

Paragon Blades

Even rarer than the masterwork charnabal sabres the paragon blades represented the absolute apex of weaponcrafting on ancient Terra. Many examples were secured by the Imperium during the wars of Unity and found their way into the armories of the Solar Auxilia, Legiones Astartes, rogue traders militant and even the Legio Custodes. Taking many different forms these weapons were all powered swords of peerless quality and craftsmanship whose blades were supremely lethal even without the archaeotech power field generators built into them. Irreplaceable and highly prized only the lucky few fortunate or well placed enough in the upper echelons of their orders could possess such weapons. Forged during the dark age of technology long before the rise of the Imperium these weapons were relics of the greatest value even at the height of the Great Crusade when the Imperium was flush with newly rediscovered technology and archaeotech relics. Whether any of these priceless weapons survived the Horus Heresy is unknown, those that may remain are almost certainly all exclusively prized relics with their own unique names and legends dating back many thousands of years. The heirloom blades of chapter masters and rogue trader dynasties and the weapons of Custodian master duelists. 

Perdition Weapons

These beautiful masterwork melee weapons were unique to the ranks of the Blood Angels legion. Reputedly based on archaeotech weaponry from the dark age of technology the perdition blades of the legion featured inbuilt micro-flamer arrays capable of dousing the weapons in scorching flames instead of the more common power field generators. It is unclear if the Blood Angels forged these weapons in mimicry of archaeotech blades or whether they were themselves all irreplaceable examples of archaeotech discovered and claimed exclusively by the sons of Sanguinius but it is fairly certain that they were all lost during the Horus Heresy. The great bulk of the Blood Angels would spill their lifeblood on Signus Prime and Terra itself leaving precious few to rebuild the legion in the wake of Horus' defeat and the Emperor's permanent internment on the Golden Throne. Swords and other weapons capable of emitting flames have been seen in the hands of various imperial heroes and champions over the centuries but whether these are surviving perdition weapons or ancient archaeotech that the perdition blades were perhaps based on or something else entirely remains a complete mystery. 

Phosphex

One of the deadliest and most horrible weapons employed by the armies of the Emperor during the Great Crusade phosphex, otherwise known as the creeping death, creates clouds of highly caustic fog that settles near the ground and expands to consume everything in it's path. Contact with phosphex ignites a victim in crawling flames that can eat through any armor or protection known to the Imperium, ceramite flakes and degrades, under-armor warps and melts. Once inside a victim's armor phosphex melts flesh and bone alike, consuming living creatures in a slow and agonizing death. Even minute exposure to phosphex can be brutally fatal and worse this creeping fog of death can persist for years, decades, even centuries depending on the environment. It burns even in airless space or underwater and is almost impossible to extinguish. Because of it's persistence long after deployment phosphex was generally treated as a weapon of last resort, deployed only against the most stubborn and intractable of foes knowing that whatever battlefield or infrastructure it was used on would be uninhabitable for many years to come. Only highly ranked officers could authorize the deployment of phosphex and in the legiones astartes it was reserved for the arsenals of the dedicated destroyer squads whose radiation and phosphex weaponry made them pariahs among their brothers. Those squads ordered to deploy phosphex would often succumb to the very weapons they wielded so dangerous was the creeping death. Only the primarch Mortarion favored phosphex as a weapon and carried several potent phosphex bombs on his person at all times. Curiously phosphex is one of the rare dark-age weapons that survived the terrible loss of knowledge during the Horus Heresy but was later destroyed by the rogue heretek Mechanicus priest Veriliad. The renegade tech-priest decided that phosphex was too terrible a weapon to exist and he chose to destroy the few remaining STC materials detailing the creation of this dread weapon. For his crimes against the machine god Veriliad was executed by a shot from the phosphoenix, a rare archaeotech handgun that fired rounds filled with the terrible combustible substance. Veriliad was consumed in the most horrific and painful way by a remnant of the weapon he had hoped to destroy.  

Plasma-Burners

 

The Dark Angels were not known as the 1st Legion for quirk of a numbering convention, they were the first legion to be created and deployed. Dark rumors suggest the first legion participated in the culling of the thunder warriors in the battle of mount ararat. Regardless of the truth of such rumors the Dark Angels were entrusted with a number of powerful and dangerous relic weapons from the wars of unification. A great many of these weapons remained sealed away in secret armories known only to the Lion and opened only in the most dire of circumstances but others were deployed widely among the legion. Among these were a wide variety of relic plasma weapons, of which the 1st Legion possessed many more and in wider variety than any other legion. One of the most brutal examples was the plasma-burner, a unique weapon utilized by the Dreadwing Interemptor squads of the first legion. Essentially plasma guns modified to spew their volatile payload in a wide spray like a flamer rather than a condensed spherical projectile these weapons were true horrors capable of dousing a wide field of fire with super-heated plasma. Flesh and metal alike would melt and vaporize under the intense heat of these deadly weapons. Squads of dreadwing warriors could even be reinforced with a heavier version of the plasma-burner known as the plasma incinerator. Although not as viciously shunned as the destroyers of other legions the dreadwing interemptors nevertheless filled a similar role in the ranks of the Dark Angels and could also deploy phosphex and rad grenades making these warriors truly horrifying opponents to face whose weapons obliterated and tainted everything they touched. 

 

Rad-Weapons

One of the oldest and most commonplace of the proscribed weapons available to the Legiones Astartes, rad weapons saturate their victims with deadly radiation, the cellular structure of organic creatures breaking down under these weapon's corrupting influence. These weapons come in many forms, from massive warheads and torpedoes capable of rendering entire continents to ash, to handheld firearms and grenades. While available to the Legiones Astartes most legions preferred not to use these weapons frequently or with much enthusiasm, relegating them to specialized Destroyer squads. These units were deployed when an enemy required absolute destruction with no regard for collateral damage. A few legions such as the Death Guard and Iron Warriors either enthusiastically utilized these weapons or saw no real shame in employing them, however most legions saw rad-weapons as dishonorable and shameful weapons. Even the super-human physiology of the space marines could not withstand the high-levels of radiation exposure using such weapons entailed leading to Destroyers often sporting rotten teeth, cancerous growths and a variety of malign health conditions despite the care of legion apothecaries. Following the Great Crusade and the Horus Heresy the use of rad-weapons would decline and eventually vanish from the armies of the loyalist Space Marines, the centuries lasting corruption too damaging to the worlds of the Imperium to countenance their continued deployment. 

Rift Cannons

Another piece of irreplaceable and otherwise forbidden archaeotech uniquely entrusted to the warriors of the first legion were the rift cannons. These terrible dark age weapons fired beams of energy that ripped holes in reality, creating warp singularities on impact. Deployment of such warp weaponry would be immediate cause for execution for any other imperial military force outside the ranks of the Imperial Household yet the Dark Angels were entrusted with a number of such terrible weapons. Today the Sons of the Lion retain only the smallest examples of this terrible technology deployed on the chapter's prized Dark Talon gunships. Even at such scale these weapons are extremely dangerous and powerful but during the Great Crusade the legion possessed much larger examples. The Dreadwing of the first legion possessed a pair of modified glaive super-heavy tanks whose primary armament was swapped out for super-heavy versions of the rift cannon and it is said the Dreadwing also possessed a strike cruiser armed with a capital-ship variant of this forbidden weapon. It is not known what happened to these extremely dangerous weapons in the aftermath of the Horus Heresy but given their absence in the ranks of the modern Dark Angels chapter it seems likely that both tanks and the strike cruiser were lost in the wars against the traitor legions, perhaps sacrificed in the Thramas Crusade the first legion fought against the savage murderers of the Night Lords legion or the many battles of the Scouring era. 

Scimitar Jetbikes

A variety of powerful anti-gravitic jetbikes were commonly fielded among the ranks of the legiones astartes and the legio custodes with the Scimitar pattern being by far the most common. The White Scars legion in particular fielded many thousands of jetbikes with the greater bulk of the legion capable of being mounted on such glorious steeds. However the Horus Heresy would severely damage the technological knowledge and manufacturing capabilities of the Mechanicus and the Imperium as a whole and anti-grav technology was one of the worst areas hit by the treachery. Following the Horus Heresy precious few jetbikes survived and they quickly fell out of use among the chapters of the adeptus astartes. Small numbers of dawneagle jetbikes remain in use by the Adeptus Custodes today and a single relic jetbike is the personal mount of the Dark Angels second company captain Sammael, an archaeotech MKXIV jetbike known as Corvex. Most recently the genius Archmagos Dominus Bellisarius Cawl has gifted a newly forged jetbike Thunder to the first captain of the White Scars Suboden Khan. Whether Cawl will continue to develop the technology to the point that jetbikes return to the armories of the adeptus astartes remains to be seen. 

Solarite Power Gauntlets

These rare and powerful variants of the more common power fists used by the legiones astartes are unique to the armories of Terra and reserved exclusively for the use of the Legio Custodes and the Imperial Fists. Forged initially for the Thunder Warriors based on ancient Terran designs these weapons were highly prized by the sons of Rogal Dorn who viewed carrying them as a great honor and symbolic manifestation of their legion icon. Solarite power gauntlets and claws were also worn by the Legio Custodes, particularly by the Hetaeron Guard and sodalities of Aquilon terminators. In the wake of the Horus Heresy few such artifacts survived intact and none are known to be fielded by either the Sons of Dorn or the Adeptus Custodes today. 

 

Volkite Weapons

 

Directed energy weapons that build up thermal energy in organic targets until they "deflagrate" or explode in a fiery outburst of heat, Volkite weapons were a mainstay of the Emperor's armies during the Unification Wars and were one of the first primary weapons carried by the nascent Legiones Astartes. However volkite weapons quickly proved insufficient to arm the growing numbers of the space marines and so the legiones shifted to the boltgun as their primary small arm of choice. Nevertheless volkite weapons would remain widespread among the legions and the armies of the Emperor and came in a vast array of sizes and power from sidearm volkite serpentas to the super-heavy volkite destructors carried by the Warlord Titans of the Legio Titanicus. The Kratos heavy assault tank of the legions was able to mount as many as six different volkite weapons at once in four different sizes. Legion support and heavy support squads would still carry several different sizes of volkite weapons from chargers to culverins throughout the Great Crusade. Volkites were far from unique to the legions astartes and saw use in the armies of the Mechanicum as the standard armament of the Skitarii battle pilgryms, hull mounted weapons on termite drills, Solar Auxilia regiments would field battle tanks equipped with volkite weapons and specialist weapon squads armed with volkites, Titans carried them and even the Imperial knights mounted several different variants of volkite weaponry. Despite the wide dispersal and relative commonality of volkite weapons during the Great Crusade the Horus Heresy would wipe out the Imperium's arsenal of such weapons almost entirely. The only volkites to be found in the armories of the modern space marines are either ancient relics rarely if ever carried into battle or a handful of "neo volkite" pistols supplied to the primaris marines by Bellisarius Cawl. Even the Adeptus Mechanicus rarely fields volkites with small arm versions carried by some Tech Priests Dominus. This once common and powerful energy weapon in the arsenal of the Imperium has become a rare oddity all but absent from the battlefields of the forty-second millennium.