This article, Kri-os, was written by Kingslayer1, and BrowncoatMando. It may be linked to any page without asking for the author's permission.
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Kri-os is a death world that has been settled by the Imperium for use as a prison world. Convicts from all across the Ultima Segmentum are sent to this world, due to its harsh environment and relative safety of the system it resides in, but the majority of them come from within the Nerio system. The same is true of the guards, some were Kashidaan Cluster refugees who came to the Nerio system and found work as guards.

It currently houses 600,000 prisoners but the number often fluctuates with riots and/or new arrivals from elsewhere in the sector.


The planet possess a singular continent named Solistus that spans an estimated 4,000,000 square miles and is surrounded on all sides by a ocean of gases mixed with radioactive compounds. It is a relatively flat landmass due to the low tectonic activity of the world and the only points of interest are the prison facilities.


While the entire planet is a death trap for humans (and most other races) it does have a small collection of highly specialized lifeforms that trek the planet's surface.

Kri-os Killer

As the name would suggest this animal is a feared predator and a nuisance for the resident humans of the prisons. Large bipedal scaled monstrosities, the Killer typically ranges anywhere from two meters to three meters tall.

They also posses two arms giving them a very human appearance while off in the distance or even at close range during a sandstorm. They use their physical similarities to their advantage as they have been spotting mimicking human mannerisms to draw in potential prey such as a runaway convict lost in the vast expanses of the wasteland that is Kri-os.

There have been extensive efforts led by the Tempered Souls chapter along with the prison guards to find and exterminate the species but thus far the Killers continue to repopulate.

Kri-os' "Corpse Eater"

A disgusting little creature, it has earned a reputation for it's palate. This species consists of scavengers that eat absolutely anything dead or dying and are remarkably resilient. They, like the Kri-os Killer, vaguely resemble the human silhouette and tend to walk in a ape like fashion staying low to the ground while dragging their knuckles. Average height is usually 1 to 1 and 1/2 meters.

Hairless, pale, and mute these creatures are a ghastly sight to say the least. Fortunately for the population of Kri-os they are fairly docile and weak. They have on occasion made their way into the pantries of the prisons looking for some easy food inciting the ire of the guards. Due to their non predatory status they haven't been hunted down as heavily as the Killer species.

It has been heavily theorized that perhaps the "Corpse Eater" and Killer species are distantly related but due to rapid decomposition of the bodies of the two creatures there hasn't been any conclusive evidence to support the claims.

Sand Grubs

These hulking horrors largely resemble the grubs commonly found on ancient Terra or on planets with vast woodlands. That is where the similarities end however as these beasts function entirely different from the innocent little bugs they share physical traits of. These Grubs range form one to two feet (reports from patrols have indicated ones much larger) and oddly enough eat the radioactive matter packed beneath the sand dunes of the waste land.

In the ecosystem they are the equivalent of the prey animal as they lack any real defensive measures. Both corpse eaters and killers have been spotted feasting upon these pest but this appears to be a last resort of sorts. They typically never mettle in the affairs of humans and have largely remained out of the spotlight.

Lupercalian Lung-Bats

A hideous reminder of the Storm Draugar's infamous invasion of Kri-os, the so-called "Great Liberation of Kri-os", or "The Black Riot". When the forces of the 13th Storm made planet fall, they inadvertently brought these horrors with them. Roughly eight inches long, made of sinewy muscle and bearing a lampery mouth full of razor sharp fangs crowned by a cluster of haunting black eyes, the Lupercalian Lung-Bat is a creature borne of the influence of the Warp itself. Lung-Bats begin their lives within the musty engine rooms of Storm Draugar warships, often found roosting anywhere excess moisture collects so that they may keep their skinless forms slick and coated in a protective layer of mucous. When displaced during Storm Draugar combat actions and planetary deployments, these ruthless parasites easily infiltrate the environment they are introduced to, taking to the skies in flocks numbering in the dozens and instinctively seeking out damp and heavily populated areas.

Capable predators in spite of their relatively small size and slender frames, Lung-Bats tend to slink out of their roosts when darkness falls upon a planet, though generally their activity depends on the temperature of their environment, moving to hunt when the temperature cools and returning to their lairs when the region heats up. These horrific abominations flutter and slither about, seeking out prey. Lung-Bats are voracious predators, readily attacking creatures of any size, gouging out chunks of flesh and burrowing deep into their victim, specifically devouring organs and intestines while the prey is still alive.

Lung-Bats reproduce via implanting developed eggs into the esophagus of their chosen prey item, strangling and rendering the host unconscious while their lungs and stomach are flooded with hundreds of Lung-Bat eggs. These larvae tend to live within the hosts system for several days, cannibalizing one another and draining the victim of vital fluids, causing episodes of extreme fatigue and hemorrhaging. If not dealt with via either surgical removal or medicinal means, these larvae will eventually emerge via chewing their way out of their hosts body and devour the corpse and any nearby lifeforms in a feeding frenzy.

Needless to say, the Lupercalian Lung-Bat is considered a dreadful and fearsome pest, actively hunted and exterminated by both guards and prisoners alike. However, the Lung-Bats nature of hunting in flocks and hiding in the most unsavory of places means that they nonetheless remain, lurking in the darkness of the prison halls and derelict cellars, awaiting the drunken guard or lone convict, always hungry for flesh.


The sole purpose of this world is to house Heretics and ruffians so it has very impressive prison facilities. Each prison maintains radio silence with the others and each rests on the very edges of Solistus, their walls overlooking the toxic seas, both measures are designed to make escape very difficult.

Each of these prisons houses both male and female inmates, who live in cell blocks divided by gender.

They also contain guard quarters and armories, inside a heavily fortified structures just outside the prison walls, topped by razor wire and guard towers with bolter turrets. The Guards serve for a minimum of 3 years, if they choose to return they have 6 months off before returning for another 3 year tour of duty.

The prisons and by extension the world as a whole fall under the jurisdiction of the regional Adeptus Arbites, the guards report to them, sending daily vox reports to the Arbites headquarters on Necro via encrypted Vox channels.

The Citadel

While not a prison as such it is still a heavily fortified structure, it contains the prison world's only spaceport- from which new prisoners, their guards and food deliveries are sent to the appropriate locations via aircraft only capable of atmospheric fight. The Citadel is the one link the prisons have to the larger galaxy and each other.

Guard Equipment

  • Flak Armor - slate gray and lacking any sort of logo.
  • Stun Baton - Non lethal "negotiation device".
  • Key Cards - Grants access to control rooms and barracks.
  • Manacles- every prisoner sent to Kri-os wears them around their wrists and ankles and are not removed by the guards until they enter their cell.
  • Short barreled Lasgun - given to the guards on the logic that it's better to be prepared for any last minute escape attempts in which a guard may be injured
  • Combat Knife - An optional bit of gear for the guards but a common sight nonetheless.

Northwall Prison (Minimum Security)

Perhaps it is a bit of a misnomer to call it minimum security as it is still above and beyond most other prisons. It has comparatively lax doctrines when compared to the rest of the prisons however and the least severe offenders are sent here.

Prisoners are fed three meals a day, the food imported from Syprios and allowed ten hours out of their cells (typically this means they work in the mines or factories for most of the time). Convicts are allowed to pursue their interests and hobbies so long as they don't have a nefarious side to them. There have been minimal problems at this facility thus far and the least amount of executions of the four prisons on Kri-os.

Guard Equipment

  • Flak Armor - Your average set of Flak armor sporting the logo of Northwall on the chestplate.
  • Stun Baton - Non lethal "negotiation device".
  • Key Cards - Grants access to control rooms and barracks.
  • Las-pistol - Your run of the mill las-pistol like any other in the IOM.
  • Combat Knife - An optional bit of gear for the guards but a common sight nonetheless.

South Point (Medium Security)

This is where your mid level offenders are sent. Here you will find murderers and other hive scum. Convicts here are given only two meals a day and only five hours of "allowed activity" (forced labor). They are strictly forbidden from access to any luxuries which leads to a considerable amount of contraband being pumped through the prison.

Many of the prisoners in this facility come from outside the Nerio system and and often come from very dissimilar cultures. There have been some riots with one actually ending with the entire prison facility getting overtaken by convicts which then resulted in a gassing of the facility.

Guard Equipment

  • Flak Armor - Your average set of Flak armor with the logo of South Point on the chestplate. Recent improvements include a rebreather, hoping to avoid a repeat of the South Point Riot
  • Stun Baton - Non lethal "negotiation device".
  • Key Cards - Grants access to control rooms and barracks.
  • Short barreled lasgun - as the contraband smuggled into the prison sometimes includes makeshift weapons the guards prefer to be as well prepared as possible.
  • Combat Knife - An optional bit of gear for the guards but a common sight nonetheless.

Famous Staff

Ezequiel Vargas

A veteran of the Vatian Imperial Guard, previously having served in the 8th corps he is noteworthy for his dedication to both personal discipline and to prison regulations. This made him enemies amongst the general population. They quickly learned not to cross him when he survived an ambush- using his skills in the bare handed variant of Eske to badly injure 6 inmates without any of them landing a single hit in return.

Antonella Cavelli
"You know how I got these scars? That's what a 'nid Ripper does to flesh. I saw my world die, you don't scare me. "
—to her would be assassins

As an Imperial Guard veteran herself she was assigned to one of the female cellblocks, quickly proving herself worthy of the responsibility, shutting down an Obscura smuggling ring and dismantling one of the prison's gangs. She too survived an assassination attempt, simply showing her attackers the scars that crossed her chest, face and arms.

East Ridge (Maximum Security)

More of a labor camp than a prison as all the prisoners despite the severity of their crimes are allowed more time for "activities" than in the other prisons. East Ridge sits atop a large vein of precious metals so the prisoners are sent down there in shifts to extract the precious resources.

When the convicts aren't thrown into the tunnels of the vast mines then they are locked inside of their cell and their only meal for the day is tossed in (only if they gathered enough ore that day). It is a relatively safe place to be posted as a guard as all of the prisoners are typically too tired from the backbreaking labor to try and cause problems.

Famous Staff

Famous Prisoners

Prisoner ER 118769

The so called "Indigo Killer" was given to a life sentence here upon his capture on Gallius in 144M1, later taking part in the unrest caused by the 12th Black Crusade. He would die of old age here in 180M41, his name still unknown to the public.

Guard Equipment

  • Flak Armor - Your average set of Flak armor with the logo of East Ridge on the chestplate.
  • Stun Baton - Non lethal "negotiation device".
  • Key Cards - Grants access to control rooms and barracks.
  • Autopistol - cheap and effective, very useful to keep order in the crowded confines of the mines.
  • Combat Knife - An optional bit of gear for the guards but a common sight nonetheless.


Home to the very worst offenders from all over the Segmentum Ultima, most of whom are on Death Row spending their days in solitary confinement. The inmates are given a single meal, slid through a slot in the thick metal cell door. This is their one contact with the outside world up until the day they are escorted from their cells to the day of their execution. It is also known to produce the hardest guards on Kri-os, dealing with daily executions robs them of any humanity.

Guard Equipment

  • Hardened Flak Armor - Full suits of standard flak armor head to toe reinforced with extra plates and padding to absorb shock.
  • Stun Baton (High-powered) - Non lethal "negotiation device".
  • Key Cards - Grants access to control rooms and barracks.
  • Short Barreled Lasgun - A carbine version of the standard lasgun, good for close quarters.
  • Combat Knife - An optional bit of gear for the guards but a common sight nonetheless.

Famous Staff

Aesom "The Switch" Maris

He worked at the Westgate institute for close to thirty years of his life and in that time executed over ten thousand convicts. He was renowned for his long career and how he never lost his nerve at his post despite serving as the executioner for the entire duration of his time there.


The Black Riot M39.999

"Stand with the Storm, cast down those who have held you chained, feed upon their souls. Be liberated in the name of the Dark Gods and the majesty of the Warp!"
—Argyle the Glutton, Draugar Lord of the 13th Storm, as he frees over a million convicted crimminals[src]

During the final year of the 39th millenium the hated traitors known as the Storm Draugar attacked the then lightly defended facilities of Kri-os with mechanical precision. Hordes of possessed Astartes, chaos spawn, and human soldiers flooded the prisons after landing on the planet's surface. The guards only postponed the inevitable for a few hours before they were overpowered by the warriors of the 13th Storm.

With legions of hardened killers and criminals eager to leave the death world the Storm Draugar gained many recruits that day. As swiftly as the invaders had arrived they fled back to the River of Exiles with more plunder and slaves than they could even manage. The attack provided the incentive to increase the number of guards stationed on the planet and to strengthen the prisons across the world.

12th Black Crusade M41.145

Kri-os remained largely untouched by the battle that took place within the Nerio System during the 12th Black Crusade. All of the prisons were put on high alert as they feared what might happen if the invading chaos fleet were to reach the lightly defended planet.

There were some convicts within the prisons who were covertly worshiping the ruinous powers while they were incarcerated and once the fleet entered the system the began riot and caused a section of the East Ridge facility to fall apart.

Unwittingly the rioting prisoners thought this was there ticket off world and ran out into the vast radioactive deserts. It should suffice to say that none of them ever reached their goals of escaping and many returned back to their prison irradiated and sick.

South Point Riot M41.170

This event is one of the few successful uprisings caused by the prisoners and resulted in the use of the prison's failsafe. What started off as a guard catching a deal between prisoners quickly escalated into a full blown riot when the guard was brutally stabbed by the inmates. The whole prison went on alert as the convicts set anything that would burn on fire and the guards in a panic began shooting wildly at any prisoner who got near. After several hours the prisoners broke into the armory and things really began to destabilize.

Eventually the majority of guards had retreated or been killed by the prisoners which led to the use of the built in failsafe. Few people are actually aware of the true nature of the riot as it was covered up by the Overseer of the facility due to the fact that any guards that were still inside were gassed along with the inmates.

13th Black Crusade M41.999

When the forces of chaos invaded the Nerio System once more Kri-os was a prime target. The traitors bombarded and assaulted the planet hoping to free the resident prisoners and take them into their ranks as soldiers. They were initially successful as they slaughtered all the guards except those stationed at the Citadel and sufficiently crippled the Tempered Souls detachment garrisoned there. After the chaos forces failed invasion of Necro Kri-os became the chaos forces fallback position. It wasn't until two months after Syprios was successfully defended that Kri-os was taken back by Imperial forces.


Many of the staff and prisoners have perished in the events of the 13th Black Crusade and a large portion of the prison facilities have been irreparably damaged thus rendering the prison world somewhat useless for the time being. Reconstruction efforts have already begun and all of the remaining guards have been sent off world and given paid leave for their involvement in the battle.


Cradle Of Disease

A small cult devoted to Nurgle just before the events of the 12th Black Crusade. During the East Ridge riot they fled outwards into the vast wasteland believing with their blessings bestowed upon them by Nurgle they would be able to withstand the debilitating environment. They were never spotted again by guards or other convicts and thus they are presumed dead but then again there is the possibility that those puny cultists somehow survived.

The Forsaken

A more recent gang born out of the 13th Black Crusade, they are unique in that they preach not the cause of Chaos but a militant atheism. They say that belief in the divinity of the Emperor or the Chaos Gods are equally invalid.

Too much evil has been done in their names, including their own unlawful imprisonment, for them to be anything but falsehoods to justify evil behavior. Furthermore if there ever were any god or gods they abandoned humanity long ago.

The Butcher's Disciples

Tales of the Indigo Killer's actions had spread all across the Nerio System even before he was captured so when he arrived to Kri-os he had amassed quite a few fans. He used this to his advantage as he formed a cadre of hardened convicts around him to build one of the most feared gangs within the East Ridge facility. The gang still exist today albeit much less fearsome and powerful as they lost the Killer to old age along with his fame.


Feel free to add at will!


"Believe me when I say you would rather be anywhere but there. If the labor doesn't kill you another con will."
—A former guard speaking to a man on trial
"Ever seen one of those terrifying bat like monstrosities? If not then you're lucky. Little monsters will scare you straight up a tree!"
—A Guard conversing with a fellow Guard
"I was framed! I wasn't even there that night!I couldn't have killed that guy I was across town robbing a ... FRAK! "
—A new arrival proclaiming his "innocence"