Enslavers
"A buey viejo no le falta garrapata. - There is no lack of fleas in old oxen."
- – Old Spanish saying
The Enslavers (also known as Psyrens, Krell, Dominators, Puppeteers and many other names by the denizens of the galaxy or more formally, Spiritus subjugator) are a strange "organism(?)" that populates the Warp. We say that it's an organism, but really describing what these things actually are is an exercise in futility, considering their supposed origins and "biology". We can say, however, that they are some of the most dangerous things that can come out of the Warp, and considering the amount of horrifically dangerous shit that populates the Immaterium, that's really saying something, as well as amongst the very oldest (timey-wimey warp-fuckery notwithstanding).
"Origins"
Trying to explain the origins of the Enslavers forces us to go back to the days of the War in Heaven. During those times, the C'Tan and their Necron slaves were beating the Old Ones and their allied races into submission, slowly but surely driving them into extinction. In their desperation, the Old Ones started creating more new races to try and stop them from going the way of the dodo, with little to no avail. This rapid creation of sapient and sentient species, alongside the tide of feelings of OCTILLIONS of beings embroiled in the war altered the properties of the Realm of Souls quite a bit, and it slowly but surely ended up altering its very nature, turning it into the twisted hellscape the Imperium knows as the Warp. It's at this point where the first Enslavers start appearing, to the absolute horror of EVERYONE and EVERYTHING.
It is not known whether the Enslavers were the first daemons, birthed from the emotions of all of this death and destruction, they were just organisms inhabiting the Warp and got attracted to the galaxy in a similar way the Tyranids did (with a hunger for immaterial energy (souls) instead of physical biomatter (flesh), or they were peaceful Warp creatures horribly warped and deformed into the abominations they would become. In any case, they invaded the galaxy in millions, following the end of the War in Heaven and basically singlehandedly stopped all remaining conflicts...by subjecting everyone involved to fates worse than being captured by the Dark Eldar... which by default is much worse than death.
These entities arrived just at the time where the Old Ones were barely avoiding extinction by the skin of their teeth against the C'Tan, who had been betrayed by the Necrons and started turning against each other. That small moment of respite turned out to be the calm before THE storm of the epoch, getting completely blindsided by this out of context problem. As such, the Old Ones and their slave species were utterly erased from existence, used as soul-fuel for the Enslavers. Combining the state of utter exhaustion with the quickness of the Enslavers reproductive cycle and thus most of the life in the galaxy was eradicated. The Necrons and the C'Tan were more or less safe from these things, due to them not having souls anymore, but the C'Tan were getting shattered here and there and the Necrons, seeing all of the clusterfuck the galaxy had become, decided to go "fuck it" and went to sleep for around 60 million years. The only known species that we 100% know that survived are the Eldar, the Jokaero, the Hrud, and the Orks. The Orks survived the way Orks always survive: they probably put spores in places not even the Enslavers could find them, but the Eldar hadn't discovered the Webway yet, so who knows how they rode out the plague. (Maybe they built Wraithbone bubbles filled with souls like the Infinity Circuit, and the Enslavers couldn't get through?). The Hrud may have just not been particularly appetizing, given their whole "age things to dust" effect on things and how hard they are to dig out of their holes, and the Jokaero may have scienced their way out of the whole situation without meaning to. The Necrons also survived, but counting them as "species" is also a rather complicated debate, considering the Necrontyr are definitively extinct, and in their place they left the automata known as Necrons. Anyway, once they managed to leave the galaxy clean of important life, they either went back to the Warp or they starved to death, leaving the way for the galaxy to recover from the cataclysm. With the millions of year passing, the memories of these creatures faded more and more, and by the time the Imperium of Man was created, those who still remembered them thought them to be truly gone...
However, this is 40k, and if something can ruin the galaxy, it will make its way to it. The Enslavers have appeared from time to time to feed upon sapient species once again, although these ones are not nearly as powerful as those from the days of the Old Ones. Well, that or the sheer blind fanatical faith of the Imperium and its effect on the Warp makes them a relative non-issue. The Calixis Sector was victim to an Enslaver infestation in 260.993.M41, however it was repelled by the forces of Mankind. Nowadays, the Inquisition keeps an eye on these abominations, considering that a quick response is the key to keep them at bay, and that the damage they can do is far greater than any form of Exterminatus
It is also believed that Trazyn the Infinite has a carcass of an Enslaver in his collection. Considering how dangerous these beings are, as well as Trazyn's somewhat lacking security in regards to live specimens (remember when he tried to make a zoo of Tyranids, only for them to escape and run amok in the planet?). It is good to know that the thing is actually a dessiccated corpse... or at least, we believe it to be so. Trazyn personally makes sure it’s dead every time he enters the room containing it... every time.
"Biology"
Now, the first and most important thing to discuss regarding the Enslavers' biology is to know whether they are daemons or not. Considering their nature, composition, behaviour, feeding habits and common habitats... we don't know. Really, if they are daemons, they share so many characteristics with regular organisms we could be forgiven to think of them as living beings, and vice versa. Both the Ordo Xenos and Ordo Malleus keep track of these things, just in case the other is wrong. At the very least we know they are older than Chaos, so they at least don't work alongside the Ruinous Powers (after all, if all the believers are eaten, there is no more emotion, and more importantly, no worship, so they would go kaput be weakened to such an extent that they would lose most of their agency, and eventually lose both their very sapience and sentience, as they'd only exist on aspects of reality such as change, anarchy, and decay...so Slaanesh would die... it’s not worth it). They may as well be the equivalent of Tyranids for the Warp, a menace that came from outside the Immaterium (or at the very least a region of the Immaterium corresponding to another galaxy) to feed upon it, in which case, that's another apocalyptic threat the galaxy has to deal with. Great. The biggest point of evidence that points to them being biological xenos of some kind is the corpse kept by Trazyn since Daemons don't typically leave corpses, they usually just return to the Warp when 'killed'. Although this too is far from certain due to the sheer, unmatched levels of power even just standard-fare Necron-tech can unleash, and which has been well-documented to be more than capable of utterly upending Warp-fuckery with the power of science. So who the fuck knows.
Physiology-wise they take a number of forms, but the most common aspect is something akin to a mix between a flea, a jellyfish and an octopus, all bloated into ridiculous proportions (The swollen area speculated to be something akin to that of a stomach, where all of the psychic energy and souls are stored). They move by floating in the air, probably using their psychic powers to levitate. They use their numerous tendrils to search for and feed upon the souls of the living, in particular psykers. Once found, they nail their tendrils inside of the victim's brain and start sucking out the poor sod's soul, while simultaneously turning it into a drooling slave, ready to fight for the Enslavers, defeating potential threats and searching for more prey. Once the victim is more or less done, they will put their eggs inside the target's brain, only for them to hatch a year or so later, making its head explode into more Enslavers. Suffice to say, if this process is not stopped immediately, an Enslaver infestation can destroy planets in a matter of decades, though they will try to be as stealthy as possible. And by the way, we don't even know whether they are a sapient species or not, so this behavior might be instinctual or just a plan hatched with the borrowed intelligence of their host. Again, very little information for us to just corroborate anything major. If the Enslavers can't get any food, they will either return to the Warp or starve to death.
Presence in the Tabletop and Vidya
Enslavers come from the early days of Rogue Trader, although most of their fluff comes from later works. Tabletop-wise, they were given rules in the Chapter Approved Creature Feature, although no models were made for them. Homebrew rules:
SPECIAL RULES
Deep Strike: Enslavers may always opt to stay in reserve and enter play using the Deep Strike rules even in missions which do not use the Deep Strike rules. Enslavers cannot contribute dice to the Enslavement pool until they are on the tabletop.
ENSLAVEMENT
Each Slave Conduit contributes 1 dice to the pool at the start of each of the player's turn.
Each Enslaver contributes 2D3 dice to the pool at the start of each player's turn.
Each Enslaver Lord contributes 3D3 dice to the pool at the start of the player's turn.
Dice are used to control enslaved units and to mind control new ones! The dice pool is used as follows: At the end of the Enslaver's movement phase it allocates dice to enslave units. At the start of the next Enslaver's turn the pool is refilled with the exception of dice that have been left with units to show they are in danger of permanent enslavement (see below).
Enslavers count as psykers but their Enslavement dice cannot be countered by any known means, such as psychic hoods or Runes of Warding.
CONTROLLING ENSLAVED UNITS
Enslaved units automatically pass all Morale checks.
ENSLAVING NEW UNITS
Enslaving new units is achieved by allocating dice to them and rolling against the target unit's Leadership characteristic. A maximum of three dice can be allocated per enemy unit and one dice is lost per full 24" that there is between the closest Enslaver and the target (ie, 24"-47" –1 dice, 48"- 71" –2 dice, control is not possible at 72" or greater).
Less than Leadership: The target is confused, in the opponent's turn the unit may only take a single move, shoot or fight action for the remainder of the opponent's turn. The unit may not take any actions or cast in the psychic phase.
Equalling the Leadership: The target is confused and does nothing, the unit can take no actions in the opponents turn. The opponent must roll a D6 for each model in the unit remove one model from the unit for each 6 rolled on the dice to represent infighting – individuals being completely controlled and killing another unit member, ones winning freedom only to be slain by the others, suicidal incidents and so forth. -1 to the dice roll if the target is a Character.
Beating the Leadership by 1: The Enslaver can cause the unit to move or shoot.
Beating the Leadership by 2: The Enslaver can cause the unit to move and shoot at +1 BS.
Beating the Leadership by 3+: The Enslaver can cause the unit to move, shoot and charge at +1 BS and +1 WS.
Permanent Enslavement: Each time an enemy unit is affected by the Enslavers leave one of the dice from their pool with it. Once three dice have been accumulated the unit becomes fully enslaved and is part of the Enslaver's forces from then on. At this point the accumulated dice are returned to the Enslavers' dice pool.
Mind Control: The Enslaver's effect gets more powerful the closer you get. Within 12" units are at Ld -2, within 24" -1 Ld. Psykers suffer an additional -1 at any range.
Slave Conduit 5 model's to a Unit.
M 8" WS 5+ BS 6+ S 3 T 3 W 1 A 1 LD 10 SV 5+ 50pts
Psychic Lash Melee -0 1 *On a wound roll of 6+ the target suffers a mortal wound.
Warp Form: Unit has a 4+ Invulnerable Save.
Warp Horror: Enemy units that are within 6" must subtract 1 from their Leadership.
Enslaver
M 6" WS 4+ BS 6+ S 5 T 5 W 5 A 4 LD 10 SV 5+ 150pts
Focused Psychic Lash Melee -0 1 *On a wound roll of 5+ the target suffers a mortal wound.
Enslave: Select a target that is visible to the user attempting to enslave the target. This may be used any number of times.
Warp Form: This model has a 4+ Invulnerable Save.
Warp Horror: Enemy units that are within 12" must subtract -2 from their Leadership, units within 24" must subtract -1 from their Leadership. Psykers suffer an additional -1 at any range.
Enslaver Lord
M 6" WS 4+ BS 6+ S 7 T 7 W 9 A 6 LD 10 SV 5 +300pts
Psychic Storm Melee -0 1 *On a wound roll of 4+ the target suffers a mortal wound.
Enslave: Select a target that is visible to the user attempting to enslave the target. This may be used any number of times.
Warp Shift: This model has a 3+ Invulnerable Save.
Warp Horror: Enemy units that are within 12" must subtract -2 from their Leadership, units within 24" must subtract -1 from their Leadership. Psykers suffer an additional -1 at any range.
Warp Eternal: The first time this model is destroyed, roll one D6 at the end of the phase. On a 4+, set this model back up on the battlefield as close as possible to where they were destroyed and not within Engagement Range of any enemy models, with D6 wounds remaining.
In Warhammer 40k Gladius, they appear as a dangerous neutral creature which can be found defending the various hovering artefacts scattered around the map, and they viciously attack players and computers alike once one is close enough. Living up to their name they are capable of psychically enslaving units (thankfully only one at a time for balance reasons) and turning them against their former allies (cept for the Necrons, for obvious reasons). You can regain control of the unit by killing the enslavers, freeing them from their power. One can also choose to kill the enslaved unit if going after the enslavers is either too risky or in the situation that they manage to escape from your grasp (like levitating out to the nearby sea), but this will grant them the opportunity to enslave a new unit yet again until they are disposed off once and for all. .
Trivia
The Enslavers to a degree bare a resemblance to The Thrint from Larry Niven's Known Space series of books. A psionic species which could dominate the minds of others in the distant past, which are also cryptically known as The Slavers. Despite their power, they were also kind of dumb. They were impulsive, had little self control or capacity for introspection and generally did not think far ahead or to the the consequences of their actions. They eventually delegated much of their scientific research to a slave species and gave them enough freedom of thought to plot the downfall of Thrint civilization. By the time the Thrint realized what was going on, it was too late. Their response was to build a giant psionic amplifier and which they'd use to broadcast a single command across the galaxy.
"DIE"
Which killed everything in the galaxy with a spinal cord, including themselves. Again, the Thrint were not that bright.
Also they poop through their mouths.