The lore is because Saturnine Centurions are drawn chiefly from support companies or armistos consularis, coveted for their marksmanship and aptitude with advanced weapon systems. So you want them staying back and firing from a distance with that pinpoint accuracy.
Saturnine Terminator command squad starts with 2 (I think I can actually assemble one!), with the option to go all melee with their WS5. In other words, double disruption fists for twice the fun, or a fist with a ranged weapon, or you can take a fist and a war axe/concussion hammer. No axe/hammer with ranged weapon, though. Boo. Oh, they can take a plasma blaster on one of their fists, which is nice. No doubling up on particle shredders or plasma blasters, rules as written, though...is that intentional? Anyway, these guys are your bodyguards who can wield the monstrous melee weaponry of Saturnine plate with a blademaster's skill.
Then you have the daemon-possessed Saturnine Terminators, named the Phraetus Anointed Conclave. No, you still have the legionary clad in Saturnine armor plate, but they just replace advanced components of their armor with containment systems to house a bound daemon. Stats wise, this does nothing, aside from giving them WS5 and the options to take the same melee options as the Saturnine command squad (see above). Only exception is that they don't get access to plasma blasters.
Why take them, then? Well, they have Warpfire Mantle, which is a cool "daemonic" ability that allows the wearer to retaliate against shooting enemies - but you must first pass at least one armor or invulnerable save - by forcing them to make a Toughness check. Fail it, and you take D3 automatic wounds with Damage 1 and AP2. No saves allowed. Mortal wounds, basically. Cool?
My Thousand Sons get a new Osiraean Prosperine Arcana, which costs 10 points and gives us Psychometry and Machine Empathy. Only for Saturnine units and Walkers, with Psychometry, we can reduce our Overload by -1, even to 0 if it's just Overload (1)! Nice. Machine Empathy heals a single wound, but obviously can't bring dead models back to life. Neat.
Anyway, lore time!
We begin with the Phoebian Accord, which is an agreement between the Emperor and the secretive Tech-Enclaves of Phoebe to keep them independent from Mars and placing them under His direct protection. In exchange, the Phoebian Tech-Enclaves pay a tithe directly to the Imperial Household, delivering and maintaining the functionality of armaments and armor specified by the Emperor. Specifically...you guess it, the Saturnine armor,
Issued to the Space Marine Legions shortly after Terra's Unification Wars ended, Saturnine armor design was derived from the Dark Age of Technology, for protective suits intended for working inside plasma reactors. Unlike Martian tech-canon, the Tech-Enclaves were the only ones able to create new technological marvels based on such ancient data, and they set about crafting Saturnine Terminator armor.
Characterized by immense domed pauldrons that house shield generators, Saturnine Terminator armor is nearly impervious to shell and shot, innately resistant to energy weapons because of exotic rare materials, and has hermetic sealing that shields its wearer from radiation. It also boasts a highly efficient yet compact reactor that generates surplus energy that can be stored to power sophisticated weapons supplied by the Phoebians as party of the Saturnine panoply. So that's where all those disintegrator weapons came from...
Wait, nope. Instead, the Phoebian arsenal, which was helped by the Emperor, consists of plasma bombardment weapons, particle shredders and power-wreathed melee weapons of gigantic proportion. No mention of disintegrator weapons? Huh?
Anyway, Saturnine Terminator armor placed far greater cognitive demand on the wearer, owing to the intricate neural uplink that connected to the black carapace, so Space Marines required some degree of cybertheurgic resonance like latent/suppressed psychic potential to unlock its full potential. Saturnine Terminator armor had nothing in common with standard equipment supplied to the Legions, so Martian Tech-Priests can't maintain and repair them. Instead, these duties fall to Phoebian attaches of each Legion force.
The poor Phoebian Tech-Enclaves were also obligated to completely disclose all their future technological discoveries to the Emperor.
To sum it all up, basically, Saturnine Terminator armor is awesome, and I'm not going to repeat how the Journal Tactica pretty much brags about how valuable an asset it is, resilient to heavy firepower and...uh, you can just buy the book if you're interested in what kind of xenos weaponry fails against it, or how commanders make use of Saturnine-clad warriors. I'm sure you can guess.
The limited numbers of Phoebian Tech-Wrights - the only ones capable of repairing and refitting Saturnine Terminator armor - meant the Legions were increasingly unable to maintain their growing stocks of damaged or inoperable armor as the Great Crusade wore on. Yikes. The attrition sees the reduction of once vast numbers of Saturnine armors to very few. For example, unlike Horus Lupercal who was able to oversee the deployment of a considerable number of operable Saturnine Terminator armor, by the time Corvus Corax was found, the Raven Guard had few, if any, remaining operable Saturnine Terminator armors. Oh, well.
By the time of the Horus Heresy, the usage of Saturnine Terminator armor and the role of their Phoebian attendants within Legion battle forces have declined, overshadowed by easier to produce and maintain Cataphractii and Tartaros Terminator armor. Fortunately for our beloved heavy shoulder pauldron armors, Vulkan, Primarch of the Salamanders, has a personal interest in restoring, constructing and maintaining them without relying on the Phoebian Forges.
Needless to say, he succeeded.
With the assistance of the Pyre Wardens, a unique sub-sect of the Salamanders' Legion Forge tasked with the ongoing trial and development of experimental wargear, he produces prototypes. The Pyre Wardens are also outfitted with the prototypes, and Vulkan commanded them to flee during the Dropsite Massacre - the Hearthfire crew is mentioned here, a nod to Gav Thorpe's Deeds Endure, the short story with the illustration that led to Saturnine Terminator armor being popularized in the fandom.
Before Horus revealed his betrayal during his voyage to the Isstvan system, Vulkan announced to everyone his Legion's success. Through subtle alterations and substitutions to its construction, the Salamanders have rendered Saturnine Terminator armor into a form that can be repaired and fabricated anew by the Martian Mechanicum and their Forge Worlds, and Legion Techmarines. The Legions are now able to retrofit their archived stocks of Saturnine plate for battle, supplement them with freshly fashioned armors, and even deploy a revived form of the towering Saturnine Dreadnought, a prototype of the early Great Crusade that was never mass produced. Vulkan generously distributed the schema, bestowing it to every Legion except the Thousand Sons (ouch!).
We have a cool list of what each and every Legion did with their Saturnine armor.
Dark Angels apparently have an unsurpassed cache of original Phoebian issued Saturnine plate, thanks to them being the 1st Legion and having access to all sorts of relics, and even during the Horus Heresy, they are still capable of fielding Saturnine armor. Most of which are wielded by the Dreadwing's Naufragia Terminators during the Thramas Crusade against the Night Lords.
The White Scars support the Librarius project, and alongside the Thousand Sons, help with the early prototyping of Vulkan's Saturnine endeavor, and this gives them access to a reasonable stock of Saturnine Terminator armor during the early years of the Horus Heresy. However, the Chondax Engagement and warpstorms delay their usage until after the Second Battle of Prospero.
The Space Wolves are reluctant to use Saturnine armor because the technology is associated with psychic practice, albeit suppressed. However, after the Thousand Sons mauled them at Prospero, they have no choice but to grab every advantage they can, including Saturnine Terminators and Dreadnoughts. These are accompanied by Speakers of the Dead and shadowed by the term "Draugr," which implies the poor Space Wolves wearing those armors do not have their minds shielded from warp horrors of the Great Crusade.
The Imperial Fists store most of their Saturnine armors in the Temple of Oaths on the Phalanx and almost all are seconded to the Retribution Fleet by Rogal Dorn, who wants to reexamine their combat capabilities when a full fabrication batch of Vulkan's renewed schema was ordered from the Legion's Forge to reinforce the defenses of the Sol System.
Blood Angel garrisons upon Baal and Canopus, unable to contact the bulk of their Legion because of the Signus tragedy, initiate a trial of new Saturnine wargear, the Saturnine "Colossi" of Baal enacting a stalwart defense of their home world during the Horus Heresy. Sanguinius and the majority of his Legion end up in Ultramar during the whole Imperium Secundus debacle, and they are outfitted with fresh Saturnine armors from the forges of Roboute Guilliman's realm. However, the survivors of Signus, upon interfacing with Saturnine plate, reawaken the darkness of that baleful conflict.
The Iron Hands viewed Saturnine plate as an erratic relic rendered obsolete by the myriad patterns of Dreadnought and automata in their arsenal. But apparently, they have been conducting research and experiments of their own?
Among the Ultramarines, the veterans of the Evocatii Chapters have the most experience wielding Saturnine plate, and they wore freshly forged Saturnine armor enabled by Vulkan's schema to fight the Shadow Crusade descending upon Ultramar. Roboute Guilliman also orders the surviving Phoebian-issued Saturnine armor refitted and used for the anticipated Ghaslakh Crusade, though they would instead be deployed in revenge for the Calth atrocity.
Obviously, the Salamanders - the poster boys for Horus Heresy 3rd edition - possess the most new pattern Saturnine wargear among the Legions at the start of the conflict, most dispatched with Vulkan to Isstvan V. Unfortunately, the entire complement would be lost during the Dropsite Massacre. Fortunately, the Pyre Warden artificer cohorts retain early prototypes and the Legion's Forge on Prometheus have already begun fabricating successive batches of Saturnine wargear, first employed by the Unscarred garrison in Nocturne's defense before being used to spearhead the Scouring of the Pale Stars.
Unsurprisingly, the Raven Guard eschewed Saturnine plate because they favor mobility and subtlety over lumbering power, with the exception of the Deliverers. They have amassed a significant complement of Saturnine Terminators by the time Corvus Corax is discovered, but much was lost at Gate Forty-Two or dispatched in nomad predation fleets into the outer darkness. Fortunately, those that remained see their suits restored in the aftermath of the Dropsite Massacre, and the Deliverers also take pride in liberating caches of newly produced Saturnine plate from their Traitor foes.
Emperor's Children revere Saturnine plate, relegating their dwindling stock to a predominantly ceremonial role. With Vulkan's gift, the apothecaries modify their Saturnine plates to increasingly debased extremes to further the Legionary-armor interface when fielding them.
Perturabo, bitter as always, is initially reluctant to field Vulkan's Saturnine armors because he is jealous at his brother's success. And also, because the bastard believes it is a waste to arm "line warriors" with such valuable assets. However, having prized Saturnine plate's capabilities, he tasks his sons with devising new forms while fabricating a host of new Saturnine armors that he modifies into brutal new forms.
Fractured, the Night Lords have various responses, with several warlords requesting the Legion's Forge fabricate the new armor, others only wanting to steal Terminator and Dreadnought armors from other Legions as trophies, while a few spurn them entirely. One Night Lords commander enlists the Dark Mechanicum Forge World of Ulan Huda to fabricate a company's worth of fresh Saturnine plate.
The World Eaters originally avoided Saturnine plate because of deleterious interactions between its unique interface systems and the Butcher's Nails' cranial implants, and so they had no intention of fabricating Vulkan's revised schema. But a twisted cult emerged, its members exulting in the resilience demonstrated by those who don Saturnine plate despite it amplifying the Nails' effect. These morons...ahem, dudes are called Indurate, often taking pride in claiming their armors from slain foes, though fresh-wrought Saturnine plate is assigned to specialist Inductii cadres who have yet to succumb to the Nails' bite.
The Death Guard highly value their dwindling Phoebian-issue Saturnine plate during the Great Crusade, and they happily fabricate Vulkan's renewed pattern...only for most of it to go to Calas Typhon's company. Typhon is canny enough to conceal the armor's association with psyarkana from Mortarion so he can facilitate their wider distribution across the Legion without the filthy hypocrite throwing a fit.
Unfortunately for us Thousand Sons, when Vulkan circulates his reworked Saturnine schema, Prospero had already been razed and our forge-holdings stricken from the directory by which fabrication imprints are allocated to the Legions. Fortunately, the Thousand Sons had participated in the earliest development stages of Vulkan's project, and Legion elements shielded from the Burning of Prospero will later deliver an array of prototype Saturnine wargear to our scattered brothers, having mastered new psychic disciplines attuned to Saturnine use.
The Sons of Horus do not have Saturnine wargear at Isstvan because they do not have access to early reproductions of the design. Nevertheless, Horus Lupercal appropriates resources to furnish his Legion ensure various Traitor Mechanicum elements and an expanded Legion Forge are able to provide his Legion with several companies' worth of Saturnine suits by the early stages of the Horus Heresy. The majority is mustered under Justaerin captain Falkus Kibre.
At first, the Word Bearers don't really care much about Vulkan's renewed Saturnine designs because they prefer daemonology, warp-craft and more profane methods of augmenting their warriors. This changes when the Phraetus and their corrupted Saturnine panoply emerge, and they become more widespread.
Apparently, the Alpha Legion might have been fielding Saturnine armor long before the other Legions because...they're the Alpha Legion. No, I don't get it either...
The Dawn of the Age of Darkness
By this point, I'm exhausted, so I'll just summarize everything...
Vulkan restores Saturnine armor, being the genius he is, and distributes the schema to everyone. Then he's sent along with the Retribution Fleet to take the head of Horus Lupercal when the latter reveals his betrayal at Isstvan III. Vulkan is hoping that only his sons are replete with the might of Saturnine Terminator plate and Saturnine Dreadnought chassis, and that the Traitors don't have time to mass produce them...yet. He plans to deploy them into the Urgall Depression.
The Saturnine Provision is a contingency he formulates because he is skeptical about Ferrus Manus's reckless assault on Isstvan V, his newly forged Saturnine assets showing up in the Urgall Depression to outmatch Horus's assembled armies. Instead of deploying them initially, Vulkan holds his Saturnine assets back in orbital reserve, within teleportarium chambers aboard the Salamanders' fleet's vessels, such as the Fire Ark and Laecertii, ready to teleport.
The battle goes as you might as expect, and then the Saturnine Terminators teleport onto the battlefield after so many of their brothers have been slain in the Urgall Depression (this is making me depressed). Joined by Saturnine Dreadnoughts, who lumber from the landing site and require a longer period of preparation once planetside, they are reinforced further by the conveyor-arks of Legio Atarus and House Col'khak. Awesome. We're gonna smash the Traitors!
The Death Guard basically died.
Unfortunately, Dies Irae of Legio Mortis, shows up and the tide turns against the Loyalists. Long story short, while scores of Loyalist troops are erased - along with Traitors because Chaos don't care about friendly fire - a company of Saturnine Terminators move into close range to poke at Dies Irae in an attempt to collapse its void shields. They are countered by Eschatae, a Warhound Titan, and not even Saturnine Terminators and Dreadnoughts can stand up to a Titan. So they get obliterated. Mostly.
Raven Guard Storm Eagle, Herros, to the rescue! A bunch of Assault Marines jump on the Warhound Titan and bring Eschatae down, at the costs fo their lives and the poor gunship (which crashed). The surviving Salamanders Saturnine Terminators then focus their firepower on Dies Irae to drive its void shields to critical levels, and when pummeled by the Salamanders super-heavy tanks from a distance, the Imperator Titan is forced to retreat. Bye, Legio Mortis!
The Salamanders attempt to fall back and regroup around Vukan, but they are annihilated by atomic fire, launched from Iron Warriors. Night Lords and Alpha Legion then swept through the area in the wake of the bombardment. Damn Traitors. DAMN IT!
The Kolarne-Distal Incident
I won't lie, this is what interested me the most. Along with the new Prosperine Arcana. I mean, Thousand Sons, man. This is what I am. Anyway, I was wondering why the Thousand Sons would get into a conflict with the White Scars, their closest allies. Magnus and Jaghatai Khan have always been bros, there's no way the Thousand Sons would attack the White Scars. Right?
Right. Turns out, it was the other way around.
Despite being a genius, Vulkan still needs help in restoring the Saturnine technology, and he seeks it from the Thousand Sons because we're the preeminent experts in psy-tech. The unique interface systems designed by Phoebian technology are similar to psy-resonance devices discovered by the Imperium and understanding them is crucial to maintaining and fabricating Saturnine wargear beyond the tech-enclaves of Phoebe. Vulkan thus reaches out to the Thousand Sons, known experts in psyarkana, despite the Edict of Nikaea forbidding us from employing psychic powers. Ouch. So Vulkan has to be discrete, because he doesn't want our Legion to be scrutinized further due to our association with sorcery.
The outermost star system of the Kolarne Circle, Kolarne-Distal is located near the Maelstrom in the Ultima Segmentum, a pocket of calm in the raging realm of the warp. During the height of the Libarius project, the White Scars and Thousand Sons establish a joint research outpost at the system's border to analyze the Maelstrom's currents and serve as a repository and locus of study for psyarkana, including the relics of Kolarne-Distal.
This Spiracle Station retains its mission of study in the aftermath of the Edict of Nikaea, unaffiliated with the Librarius project and now a hermitage fo sorcerer-wrights who no longer have any place in the Imperium they once served. Fortunately, Vulkan gives us a place and sends a Pyre Warden artificer order's vessel to provide the garrison of Spiracle Station the initial prototypes of his attempt to redevelop Saturnine Terminator armor.
For two years, the Thousand Sons and White Scars work on restoring Saturnine wargear, maintaining contact with the Salamanders on their progress, but they are cut off from the Imperium when Magnus accidentally broke the Webway in Holy Terra, and a warpstorm swallows Kolarne-Distal whole. Fortunately, the system remains untouched despite the surrounding systems being devastated.
Unable to communicate with the wider Imperium and discovering that any attempts to leave the system will prove fatal, the Thousand Sons and White Scars have nothing better to do but continue restoring Saturnine armor, and they succeed. The Ruinstorm then blows away the Maelstrom, connecting Spiracle Station to the rest of the galaxy again. Yay! However, their first contact is with a strike cruiser, Endless Path, and its White Scar crew going insane and accusing the Thousand Sons of treachery. Even though we harbor them and allow them to dock, they immediately draw their weapons and try to kill the confused Thousand Sons.
Okay, he did tell the Stormseer Nikudaar and the Numerologist Okhafor an account of the Horus Heresy, the burning of Propsero and the condemnation fo Magnus and the Thousand Sons before he decides to go all psychotic murder on us. Nikudaar and the White Scars in Spiracle Station remain on our side and end up killing the crazed captain. The rest of the White Scars crew from the Endless Path end up going berserk and try killing both Thousand Sons and their White Scars brethren on Spiracle Station alike.
36 White Scars and 21 Thousand Sons versus three times that number of White Scars legionaries. Guess who won? Well, the guys with Saturnine armor, of course. Needless to say, the White Scars-Thousand Sons allied Saturnine force annihilates the insane White Scars attempting to murder them, and the White Scars garrison pretty much takes the Endless Path and leaves the system in search of their Primarch, Jaghatai Khan. Meanwhile, the Thousand Sons board Paroxysm, which is a XVth Legion vessel, and go their separate ways, in search of surviving Thousand Sons.
Being bros, they split the Saturnine armor and psyarkana stored in the vaults of Spiracle Station among themselves, abandoning the outpost, and sharing the fruits of their labor. And that's how the Thousand Sons get our Saturnine armor. Yay?
Oh, by the way, the crazed captain and his crazy crew? Before arriving at Spiracle Station, they came from the Prospero system, right after civil strife in the Vth Legion instigated by none other than the Brotherhood of the Dawn Sky, which they belong to.
The War of Bitter Iron
Iron Hands versus Word Bearers, basically. For some reason, the Iron Hands outnumber the Word Bearers (huh?) as the former launches a vengeful crusade toward the latter's home world of Colchis. Anyway, this specific account is the Sundering of Milhand, a diminished Forge World who has lost much of its military prowess after its small Titan Legio - Legio Ablutum (Cleansing Flame) - became Blackshields, and they were pretty much raided by Word Bearers and the Legio Mordaxis.
Interestingly, the Iron Hands fleet also has a super "kingship" of their own to rival the Word Bearers' Abyssal-class ships - a shard of Medusa's shattered orbital ring granted locomotion named Memorius. It's slow, though...so pretty much the whole story takes place before it arrives in orbit of Milhand and ends the poor Forge World with its colossal firepower.
Despite its diminished stature, Milhand is still vital in the Word Bearers' efforts and their defense of Colchis system due to the armor, munitions, equipment and weaponry they manufacture and supply. By the time the Iron Hands arrive, the Word Bearers are pretty much scrambling to get as much munitions, armor, equipment and supplies as they can off-world, for the larger war-effort. Obviously, the Iron Hands intend to stop them, and perhaps requisition a good chunk of those war materiel for themselves.
Long story short, the Iron Hands deploy in force, their superior numbers overwhelming Word Bearers defenses and overrunning them. Cataphractii and Gorgon Terminators are dispatched into the forge complex and fight their way through automata, servitors and even the machinery of the forge-complex itself. While the surface battle go well for the Iron Hands, their Contemptor Dreadnoughts and a single Saturnine Dreadnought pretty much making mincemeat out of the poor Word Bearers left behind to defend a shrinking cordon - and despite this cool scene where they merge the void shields of their Stormbirds together to make a last stand - the Saturnine Dreadnought pretty much obliterates their protection with his graviton pulverizer and inversion beamer. Nice.
The Cataphractii and Gorgon Terminators, on the other hand, don't fare as well. They stumble upon the cursed platform where daemon-infused Saturnine plate is being manufactured and anointed, and a bunch of Phraetus Anointed Conclave teleport in and begin slaughtering them. Despite outnumbering them two against one, the Iron Hands Terminators are wiped out, in exchange for only a single fallen Phraetus Anointed.
Similarly, twelve Phraetus Anointed teleport into the Word Bearers' defense to save them from the Iron Hands Breachers, tanks and walkers, but they got absolutely butchered. The Iron Hands Saturnine Dreadnought destroyed four of them while the Contemptor Dreadnoughts crushed two. With half their number slain, the remaining Phraetus Anointed basically beat it out of there via daemonic teleportation or whatever. The rest of the Word Bearers attempt to flee, but most are cut down by the sheer firepower the Iron Hands bring to bear, including anti-air fire from Deredeo Dreadnoughts.
Memorius proceeds to wreck whatever Word Bearer ships that remain in orbit, and Milhand now falls into the hands of the Iron Hands. Yes, that is on purpose. Ahem, anyway, the Iron Hands claim bloody salvage from the fallen Phraetus and Word Bearers, and they end up creating their own distorted Saturnine armor, known as Helwrought. Huh, okay.
The Bloody Toll of the Saturnine Renewal
The Solemn March sees the Ultramarines Saturnine Terminator squad Alepho march to the aid of Highborn Wardens and Evocatii battalions in the Decalian District in the world of Armatura, braving all sorts of firepower from Fire Raptors or ambushes, only to find them all massacred. Sad, grimdark.
The Siege of Baal is about the Saturnine Terminators of the Colossi standing guard over Baal, the 3,000 strong garrison supplemented by many times their number of bonded Solar Auxilia Cohort troops, such as Saiphan Elevatii, Gilded Sentinels and the Fusiliers of Canopus. Oh, and alongside sheltered Shattered Legions. They protect Baal from Traitor attacks after the perceived tragedy of Signus, saving hundreds of Legionaries and thousands of Solar Auxilia. Chads, every one of them.
During the Crucible of Nuceria, the Indurate Terminators employ Saturnine plate in mass against the elite cadres of Invictus Suzerains as Guilliman engages Angron. After the Ulramarines withdraw, they are suddenly attacked by fellow World Eaters, keen to claim the Saturnine suits as their own.
When the Inwit Cluster is attacked by Traitors, the world of Terros IV resist Emperor's Children raiders, with Bilatt Svenor of the Inwit Empire's Void Salvage Guild organizing a stalwart resistance from the world's hardy hive gangers and rig-hands. Fortunately, just when supplies and morale are running low, Imperial Fists Saturnine Terminators teleport into Terros IV and kick the Emperor's Children off the planet in style, allowing them to resume supply of promethium to the Loyalists.
As previously mentioned, Perturabo is initially reluctant to fabricate Saturnine armor because he thinks it's a waste for his line warriors, but he changes his bitter mind when he witnesses the endurance of Saturnine Terminators and Dreadnought chassis in Isstvan V. Mass manufacturing them, he deploys them during the Siege of Inwit, now having access to company-strength formations of Saturnine Terminators supported by many Dreadnoughts. These are known as Tekathikos, the Mountain Breakers.
This leads to the Imperial Fists in the Inwit Cluster specially designing hunter-killers with specialist weaponry to prioritize the destruction of Tekathikos before all others.
