Summary: An implacable assassin robot has been stashed in an abandoned facility from the Dark Age of Technology. Upon being unsealed, it escapes, searching for its target. Upon reaching any nearby civilization, it erroneously identifies various NPCs as its target, killing them one by one.
Discovery: The abandoned facility is immediately obvious from the outside, although overgrown by the jungle. Inside the facility is a monitoring room overlooking a chamber containing two dozen different pods. Many of the pods have been broken open by collapsing debris as the roof gave way under time, others have rusted shut or fallen apart. Most terminals in the monitoring station are broken, but a few still function on reserve power from a handful of still-functioning batteries. Upon being activated, a display shows an iconographic view of the two dozen pods, all displayed in red except for one, still blue, at the far end of the room.
Exploration: Characters who are weary or paranoid might want to just immediately blow everything up. The pods provide 16 armour as cover, so the machine assassin lurking in the one surviving pod will be difficult to immediately blow to smithereens, not the least because of its general endurance, however if the characters do drop enough explosives on this problem to vaporize it before it even wakes up, then that’s the end of it. Nothing can be gleaned from the debris left behind.
A Difficult(-10) Tech Use or Ordinary(+10) Forbidden Knowledge (Archaeotech) check can unlock the terminal, which gives several options. Power can be cut to the whole facility, at which point the machine assassin in the functioning pod will switch to backup power and run out after about two years’ time. That’s outside the scope of the campaign, but so long as no one else finds the place it’s an easy way to disable the threat.
Asking the system to run a diagnostic will reveal that the machine in the one active pod has received some CPU damage, but most systems remain functional. At this point, the characters can put the machine into standby mode and open the pod up to repair it, however the check for actually repairing the damaged machine is Arduous(-40) for a Forbidden Knowledge (Archaoetech) check and Hellish(-60) for a Tech Use check. Any failure will cause the machine to activate automatically.
The machine assassin can also be activated, in which case it will malfunction slightly, believing itself to have been assigned a new target. None of the characters match the target, but several NPCs from nearby towns or cities do match (especially the relatively close Brandt’s Landing). Upon activation, the machine will leave its pod and begin heading to the nearby river, which it will follow to find any major population centers where it can find information on its target and quickly find several erroneous matches. These NPCs can be anyone you want – old friends or enemies of the characters or brand new characters randomly selected from an unsuspecting crowd. The machine’s target identification programs are completely glitched out from Chaos interference from the Age of Strife, and while the possessing daemon was reclaimed by the Warp when Slaanesh was born, the damage done to the circuitry remains. Because the targets are being picked at random from an in-universe perspective, there’s no reason not to pick them for narrative convenience out of universe. If the characters try to prevent the machine assassin from leaving, it will engage them, but otherwise it will ignore them. If the characters ignore the machine and go on their way, if they have any contacts in Brandt’s Landing, those contacts will get in touch with them if at all possible on the following day to let them know that a mysterious assassin has killed one of their allies in the city. If they have no contacts in Brandt’s Landing, give the machine another few days to reach either Grey Harbour or Imberkavitas (whichever is more flush with contacts the PCs don’t want to lose) and then have the characters notified of the attack.
Confrontation: The machine isn’t stupid. It will make some effort to blend in with its surroundings and will make use of its synthetic skin to appear human for as long as that lasts. Minor damage to the synthskin caused by impact or slashing “wounds” (whether or not they penetrate the machine’s Unnatural Toughness), including those from grenade shrapnel, will be covered up with clothing to maintain its cover, including masks if necessary. Only if something like a flamer is used to completely melt all the skin off (again, regardless of whether any real damage is caused through the machine’s Unnatural Toughness) will the machine take to hiding from notice altogether between its strikes.
The machine is not a specialist in stealth, however. Upon finding its target, it will engage straightforwardly, attacking them directly with whatever weapons are available – most likely including the plasma gun it steps out of the pod with, but if that runs out of ammo (which is fairly likely over the course of multiple engagements) the machine may be forced to acquire new weapons instead, likely limited to the autoguns and lasguns used by local defense units, although it may be able to get its hands on a heavy bolter if it storms an armory in Grey Harbour or Imberkavitas. It is additionally nearly impossible to kill on account of not only its high Unnatural Toughness, but its immunity to death from shock nor from any amount of trauma to its limbs or head. All important processors are housed in the well protected torso, and only critical effects that involve damage to that torso (including some like arm rending 9, which slices through the arm and into the torso) can kill it. If the machine assassin loses a body part, however, any strikes to that body part instead hit the nearest intact location (i.e. a hit roll of 24 would normally hit the left arm, but if the machine’s left arm has been blown off completely, you instead round down to 20, a hit on the right arm – had the hit been 26, you would instead round up to 31, a hit on the body).
Rewards: If the characters successfully repair the machine assassin, they can program in new targets any time they have physical access to the machine (no new check is necessary, they’ve already got the admin password), and the amount of background Chaos in the galaxy has dropped off enough since the Age of Strife that it will serve fairly reliably.
The only exception is when it comes within close proximity of strong Warp phenomenon. Whenever a psyker triggers psychic phenomena within a number of meters equal to the effective psy rating of the power used, it causes interference with the machine assassin. For example, a psyker whose psy rating is normally 4 but who is casting a power at psy rating 3 instead, and who triggers psychic phenomena, will cause interference to the machine assassin if it is within 3 meters of the psyker’s location. If the psyker triggers perils of the Warp, the machine assassin experiences interference if it is within three times the effective psy rating of the power that triggered the peril, and is possessed if it is within a number of meters equal to the effective psy rating of the power that triggered the peril. Using the same example above of a psyker with PR 4 but casting at 3, if that power triggered perils it would cause interference to a machine assassin within 4-9 meters and cause the machine assassin to become possessed within 3 meters. A creature with the Daemonic trait is treated as though it were constantly triggering perils of the Warp at psy rating equal to their Daemonic trait for purposes of interference or possession of the machine assassin. For example, a bloodletter has the Daemonic(4) trait, which means the machine assassin will experience interference within 5-12 meters of it, and will be possessed if it comes within 4 meters of it. Other Chaos phenomenon, like portals or Chaos corrupted locations, may have an aura that causes interference and/or possession if the machine assassin comes too close, at the GM’s discretion.
When experiencing interference, the machine assassin glitches out, twitching and jerking and completely unable to focus or parse its surroundings. It becomes stunned for one round (and if the effect is continuous, like that of a daemon, it will remain stunned until after it leaves the radius of the effect). When possessed, the machine assassin is possessed by a random daemon, not necessarily one allied to the daemon (if any) that caused the possession, and begins acting on its own whims, which is usually to kill any mortals nearby in a blind rage.