|Strength||Potentially thousands (Luther had originally raised ~45,000 during the Horus Heresy)|
|Specialty||Evading/trolling the Unforgiven|
|Allegiance||Various (see below)|
|Colours||Pre-Heresy Dark Angel black|
REQUESTING DATA ACCESS, security_clearance: INQUISITOR. Processing...
Database error #0754339867, access: DENIED
Greetings Inquisitor Yzaguirre, the information which you are attempting to access is classified and may no longer exist. Your service record and citizen number have been logged and recorded, any further interest in this subject on your behalf may result in the unfortunate early termination of your career.
REQUESTING DATA ACCESS, security_clearance: INNER_CIRCLE. Processing...
Adeptus Astartes DNA confirmed, scanning... chapter: Disciples of Caliban, rank: Company Master, access: GRANTED
Welcome son of Lion El'Jonson, here is the latest intel on the movements of the Fallen ones. As always this information is FOR THE EYES OF THE UNFORGIVEN ONLY and takes precedence over all other duties, no matter how urgent. For the Emperor and the Lion!
Incoming Data Stream...
The Fallen Angels are renegade members of the Dark Angels Legion who turned on Lion El'Jonson during the Horus Heresy. They have a thousand contradictory stories and a thousand contradictory motivations, from full on Chaos worship to acting on Luthor's lies to political shenanigans. To those Dark Angels who know of their existence, they are simply known as "the Fallen".
History of The Fallen
Okay, so after the Emperor found Caliban, Lion was made commander of the Dark Angels, and they began recruiting from Caliban's population, including taking on many of the Knights that served in the Order with Lion, amongst whom was his friend and mentor Luther. After some time had passed in the Great Crusade, a cadre of 500 Astartes made up of a mixture of both Calibanite and Terran Dark Angels were relegated to garrison duty on Caliban while Lion went off and fought in the Crusade with the larger bulk of his legion. This apparently caused no small amount of discontent among the garrisoned Angels, many of whom were once high ranking Chapter Masters and Captains who were now under the command of Luther, who was not even a Space Marine. In addition, Luther and many others felt abandoned by their Primarch or they felt that the old Calibanite way of life was being eradicated by the takeover of the Imperium. For their part, the Terran Dark Angels saw the Calibanites clinging to old traditions and oaths, noting that, amongst other things, instead of swearing "For the Emperor", they would instead swear "For Caliban", and saw them as being insubordinate. Chaos was quick to take advantage of their resentment and convinced them to betray their Primarch.
Over the course of the Horus Heresy, the garrisoned Dark Angels had no idea that the galaxy was at war around them; this was partly because events on Caliban, such as noble uprisings and daemonic cults, prevented them from looking outwards, but also because Luther had taken control of planetary communications and Cypher was doing his best to keep Luther either distracted OR prepared for something (the jury is still out on that one), so Luther wasn't paying enough attention until some Knights-Errant showed up to determine his loyalties, which accidentally let the cat out of the bag.
By mid-Heresy, Luther had enlarged the garrison up to a sizable force, all trained in the traditions of the old Order of Caliban, managing to reduce training cycles for new Astartes from eight years down to an optimal 24 months (two years) and seemingly could produce around 5000 marines per cycle. As of the time Luther and Zahariel become aware of the Ouroboros, Luther cancels further deployment of these marines until further notice. When Belath comes to collect them whilst the Horus Heresy was in full swing, Luther has a force of around 45,000 warriors under his command (Belath came with enough transports for 30,000 men, then Astelan points out that it would leave less than half that number on Caliban) With this force he had already decided to declare independence from the Imperium.
At some point after the Siege of Terra and the long aftermath referred to as the Scouring, Lion El'Jonson returned to Caliban, and the Dark Angels garrison opened fire on his fleet. Heading to their fortress-monastery, Lion fought Luther in single combat whilst the Dark Angels continued their orbital bombardment. Unfortunately, Caliban was never really tectonically stable, and the force of the bombardment caused the planet to break apart... somehow. The only thing to survive was the fortress-monastery. By the time Lion's loyalists got in, Luther was a gibbering wreck and Lion was nowhere to be seen. The garrisoned Dark Angels were apparently thrown through the Warp and scattered across the stars. Ever since, the Dark Angels have hunted for the Fallen Angels to restore their honor in the eyes of the Emperor.
However, things are a bit more complicated than that...
It has been shown that not all of the fallen angels are followers of Chaos, and many (possibly even most) of them regret their pre-Heresy actions and realize that they were wrong; these members of the Fallen have gone into exile and try to blend into the local population and live a "normal" life, although quite how a seven-foot tall post-human with enough muscle to tear a bear limb from limb and the external ports from his Black Carapace poking through his skin is supposed to just "blend in" with anyone outside of the Deathwatch is anyone's guess.
Not only that, but the Fallen were said to be fighting among themselves before the Lion even arrived in orbit; as mentioned previously, many of the Terran legionnaires (and some Calibanite Dark Angels too) were uncomfortable with the way that Luther was comporting himself and tried to get a message out to Terra or the Lion to inform them of what was happening to their planet. They managed to amass a force of several thousand Astartes and tried to storm one of the astropathic relays but were double-crossed by one of the First Legionnaires, Astelan, a guy who was one of the first 5000 space marines EVER and remembered the Thunder Warriors, who sought his own advancement and was unhappy with the way that the Lion commanded the legion that "used" to be mostly his before the Lion showed up. These Imperial-Loyalist forces were all rounded up and placed into dungeons underneath the Rock.
- It is a testament to Astelan's over-bloated sense of self-worth that he believes the Dark Angels would be better off under his command, especially considering that despite being one of the first 5000 Astartes ever created he did not rise to the position of chapter master until after the Lion took control of the legion. His attitude towards the Lion and the newer Dark Angels is very similar to that of the Custodians in Master of Mankind, viewing all those that came after as below him; after all, he was one of the first, and was directly commanded by the Emperor in person; why should he take orders from a lesser being? He is very much a mercenary at heart, and as long as you remain the biggest kid on the playground then he will be your best friend, but as soon as an even bigger kid shows up you can bet that Astelan will do what is best for Astelan.
Therefore as the Heresy has progressed several different factions of Dark Angels emerged:
- The Dark Angels who follow the Lion, either accompanying him to Imperium Secundus on the far side of the Galaxy, or who are accompanying his Paladin Corswain on the other side of the Ruinstorm.
- The Dark Angels who were on Caliban and remained loyal to the Lion and the Emperor, but who were ambushed and imprisoned beneath the Rock.
- The Order, who rejects their Primarch and Emperor, who follow Luther and yearn for a return to the glory days of a free and independent Caliban regardless of whether Horus or the Emperor win the Heresy. To ensure Caliban’s “freedom and glory” Luther and the Order decided it would be a good idea to expand upon their power base by conquering… did I say conquering? I meant liberating all the nearby inhabited systems thus bringing them under Luther’s command. But you know, conquering and subjugating entire populations in order to accelerate your own personal agenda is only a bad thing when the Imperium does it; when the Order takes control of your home by military force it’s all in the name of “freedom”… yeah, this is not going to end well. (This would also make the Dark Angels' big secret a lot worse; if in their rage and grief they had to “deal” with these renegade systems that had knowledge of what had happened on Caliban… just think about it)
- The First who follow Astelan, who reject the Lion as an unworthy liege but at least put lip service to the idea that the Emperor is their true master. At the current point in the storyline, Astelan supports Luther out of political convenience. (Not all the "First" follow Astelan; many sided with the Lion and are imprisoned with the others beneath the Rock.)
- Zahariel's Mystai, who have secretly fallen under the influence of the Ouroboros and want to see it freed from its prison buried within Caliban. Closet Chaos worshippers even if they don't realise it yet.
- The Watchers, and the (possibly former/deceased) Lord Cypher, who have their own agenda that no other faction really knows about, but who know the truth about Chaos and the Ouroboros and want to keep it contained.
- The current Cypher (who may or may not be Zahariel), whose motives are a complete mystery.
Over the years, some of the captured Fallen have claimed that it was Lion El'Jonson who was the traitor and took his sweet time to get to Terra, implying that Lion El'Jonson was trying to wait and see who would win the civil war and side with the victor. This is probably the Fallen lying, as they would have no way of knowing what the Lion was actually doing at all, considering he and his Legion would have been scattered across the Galaxy and never called home to see how things were going. The Lion certainly had reason to be displeased with the Emperor (Horus correctly suspected that he resented not being chosen as Warmaster, as he was the "First" Primarch as well as the Primarch most renowned for his tactical genius), however the consensus viewpoint amongst fa/tg/uys seems to be that these are just the ramblings of tortured Fallen repeating lies told to them by Luther and that the Lion's ABSOLUTE LOYALTY remains intact. Whatever the truth is, only the Emperor knows, and he isn't talking. Mostly because Horus ripped out his tongue and his vocal cords have faded to dust, but that's beside the point. The book Fallen Angels did note that El'Jonson supplied Perturabo with extra siege weaponry before the Drop Site Massacre on Istvaan V in exchange for the Iron Lord supporting him as the new Warmaster when Horus was slain. He didn't realize that the Iron Warriors were traitors until it was too late. Similarly, one confrontation between the Lion and Konrad Curze ended with the latter correctly predicting that the Lion's attempts at pursuing him and the Night Lords would be used against him as evidence of his disloyalty.
However, the rantings of the captured Fallen Angels when they accuse the Lion, the Imperium or each other of misdeeds has to be taken with copious amounts of salt:
- They cannot be represented as a picture of the whole truth, especially in that there were Loyalist-Fallen & Traitor-Fallen fighting EACH OTHER on Caliban before the Lion showed up, so they do no represent the views of a unified group.
- Many Fallen are simply liars who will say anything to protect their own skins. Astelan in particular is now confirmed to be a liar and that he is as culpable a traitor as any other (just not a capital T Traitor; he's disgusted by Chaos) despite his protests in 40k that he was actually a loyal subject of the Emperor (if not the Lion).
There are even reports that some members of the Fallen may be Closet Loyalists attempting to subvert Chaos from within by drawing the Dark Angels' attention to where it is needed most only to disappear once the Dark Angels arrive leaving them free to battle the true threat to the Imperium, just as planned.
Amongst the known Fallen Angels the most famous is Cypher whom Games Workshop just gave a dataslate full of AWESOME AND WIN. Check this shit out, the only guy with a BS of 10! He's more of a sniper than a sniper!
It is also highly possible that the Death Watch commander Israfil (the only Black Shield commander in the history of Death Watch named in lore) was in fact the Fallen ex-Chief Librarian Israfael (the one who recognized Zahariel was a psyker); this suspicion is fed not only by their similar names, but also by the strange death of Israfil during a xenocidal campaign which also involved Dark Angels forces and the inability to recover his body.
Some other Fallen decided to make the most of their shit sandwich and pledged themselves to Chaos. Among these were an Astartes named Vortigern and his Lost Lions warband, who joined the Black Legion when it was in its infancy. Vortigern became part of its ruling council, the Ezekarion, and it's partly down to him that they're still intact. When the First Battle of Cadia saw the Black Legion caught between the Black Templars and a surprise attack by a heap of Nine Legions ships, Vortigern was the first to get a decent number of Black Legion vessels to safety.
What counts as Fallen?
While the Unforgiven put all of their focus on hunting their wayward brethren, there is an important distinction between "true" Fallen and just another traitorous space marine. In Pandorax, one of the major villains is a renegade Consecrators Space Marine, who refers to himself as Fallen and has even had contact with Cypher.
Once he was caught, he refused to be broken and repent in the dungeons of the Rock and claimed that he would escape if they did not kill him. To which Azrael & Asmodai laughed in his face. (YES, ASMODAI ACTUALLY LAUGHED!) Then they told him that the "true Fallen" were led unknowingly by Luther into rebellion and can still be saved if they repent, while his descent into heresy was his own fault and he was not led astray, finding Chaos because of his own selfish desires whatever they may have been. So Dark Angels simply consider other more recent renegades as traitors worthy of only death.
So they decapitate him.
Ophidium Gulf Crusade incident
The precise details of this incident are somewhat sketchy, not being helped by the fact that Games Workshop have released several seemingly conflicting versions of the event. What they all agree upon however is that the Black Templar Strike Cruiser Ophidium Gulf disappeared in mysterious circumstances shortly after making contact with a larger Dark Angel force and taking captive a Fallen Angel in a "joint" operation. Initially reluctant to comply with the Dark Angels' demand to hand over their prisoner, they realise that the Dark Angels aren't messing about when their ships start powering up their weapons and, greatly outmatched, are left with no choice but to relent. After handing over the prisoner they make a single astropathic communication on way to the system jump point but are never heard from again, the implication being that the Dark Angels ambushed them to prevent the secret of The Fallen from becoming public. Which is stupid of the Dark Angels. Everyone would assume that Cypher was the only renegade Dark Angel and would shrug off the threat delivered to the Black Templar ship as the Dark Angels protecting their honor by wanting to be the ones to deal with the traitor(?) to their Legion. Instead, their actions blew the whole thing out of proportion.
There are several interesting notes we can take from this:
- This is the first (known) time that any chapter outside of the Unforgiven has had contact with the Fallen; the Black Templars immediately realized that the individual was an Astartes however they chose to take him prisoner rather than execute him as a heretic giving some credence to reports that not all Fallen are Chaos worshipers.
- In the story as told in White Dwarf 312, the Fallen taken prisoner is none other than Cypher, who remarks upon seeing the Templars "You are not the lapdogs of the Lion... how curious"; the Templars agree to meet the Dark Angels at a pre-arranged point for a prisoner transfer but are never heard from again afterwards and Cypher mysteriously and inexplicably vanishes from his cell, thus proving he is awesome! Other versions of the story have the prisoner as wearing ancient Mark 1 Power Armour and seemingly being rescued by other Fallen masquerading as Dark Angels before the real Dark Angels presumably turn up to destroy the Ophidium Gulf to stop the story leaking out.
- When the Unforgiven say that they're willing to do anything to keep their secret safe, they're not kidding; murdering brother Astartes is pretty fucked up by the moral compass of most loyalist Chapters, for the Dark Angels however it's not something which they will hesitate to do or agonize about later as long as they keep their secret safe and "honour" intact. In fact, it's probably not too big a stretch to say that no other loyalist Chapter is as close to being excommunicated from the Imperium as the First Legion and it may even have already been so were they not tolerated due to their strength and importance.
- The Black Templars have not forgotten about this incident, and have strong suspicions as to the eventual fate of their battle brothers; despite their apparent mutual affinity for entering battle dressed in robes, the Dark Angels (whom were already regarded with suspicion by the Templars' for their rampant secrecy) are now openly distrusted even more than the Templars distrust any Chapter who aren't sons of Rogal Dorn, which is saying a lot as the Templars distrust pretty much everyone anyway. Seeing as how the Templars are well above Chapter strength, could probably count on support from the Space Wolves who are also above Codex strength (though how above both are is a matter of debate) and whose not-so-friendly rivalry (depending on which codex you read) with the sons of Lion El'Johnson has on occasion spilled into open conflict, we could make the supposition that if the combined Unforgiven (the Dark Angels and whichever successors they call in) weren't impressively powerful then the Templars and Space Vikings might have tired of waiting for the Inquisition to dig up the Dark Angels secrets and taken matters into their own hands. The Dark Angels sure do like making powerful enemies! They also requested that the Inquisition make a formal investigation, which has been indefinitely suspended after the Inquisitor in charge of the investigation "disappeared".
- A recent event (as in its form the new Iyanden supplement) reveals Dark Angels only seem to care about the Imperium finding out their little secret, as a similar event happened when Iyanden was fighting a chaos mini-empire ruled by a Fallen. Only here the Dark Angels didn't hunt down and kill the Eldar (granted it may be due to their use of the Webway). Meaning they're more willing to trust and work with Xeno Scum than Imperial forces, except that the Inquisition are a rightfully feared threat to ANY space marine chapter. Of course, it's not like the Eldar are going to tell anyone in the Imperium (or be believed if they did) or would even understand the concept, or know about the Dark Angel paranoia. Of course seeing how the Eldar only turned him over because they've read their minds... (It's implied that the Eldar let them take the Fallen, because they knew he would suffer more at the hands of the Dark Angels. Grimdark.)
- Strangely however, the Ophidium Gulf Incident isn't mentioned in later editions nor has it been expanded upon since. In fact, it seems to have been retcon'd out. Between the Battle of Piscina IV (997.M41), the Third War for Armageddon (998.M41), and the events of Master of Sanctity/The Unforgiven (999.M41), the Dark Angels chapter wouldn't have any Battle Barges or Strike Cruiser Squadrons anywhere near the Ophidium Gulf during the supposed Incident (also 998.M41). Oh, and in Master of Sanctity, Cypher - who I'll remind you, was the Fallen captive at Ophidium - just walks right up to the Dark Angels anyway to deliver a warning, meaning he would have little reason to run away at Ophidium. So... who the fuck were the Dark Angels who attacked the Ophidium Gulf? It seems some dickery is afoot...
Ironically in the recent Fallen comic series, the Dark Angels strike force commander, Captain Seraphus, is insistent on his refusal to fire on the Grey Knights & Inquisitorial vessels, helmed by Justicar Leofric and Inquisitor Sabbathiel, in Calaphrax Cluster in M41 when the latter demand permission to board and investigate the Dark Angels for signs of heresy (whether his refusal to shoot is either out of knowledge that doing so is heretical suicide despite the Dark Angels battlebarge' superior size and firepower or due to the distaste of shooting fellow loyalists is up to debate). In the other hand, he was more than willing to dispatch a boarding party led by Veliath while they are distracted by a battle with Iron Warriors to board the Inquisitor's vessel and discern if she knew too much and if she must be "dealt with" appropriately.
More than any other Chapter, the Dark Angels and the Unforgiven fear what would happen if the Grey Knights should become involved with a hunt for the Fallen Angels. Making Inquisitors or even fellow Space Marines "disappear" is one thing. Trying to do the same to Space Marines from a Chapter designed to fight and kill Daemons? Near suicidal, even by 40k standards. However, as revealed in the novel Pandorax, it's irrelevant. When the Black Legion attempted to open an ancient warp portal the Grey Knights were sent to the planet Pythos in order to seal the breach and deal with the demonic incursion, Supreme Grand Master Draigo was unable to wait for reinforcements from among his own forces due to his Chapter being scattered around the Imperium in response to a myriad of daemonic threats, instead he opted to enact an old oath sworn to the Grey Knights by the Dark Angels. Azrael had initially refused to honour the pact, considering it to be tantamount to blackmail. His mind was soon changed when Draigo revealed an interesting nugget of information gleaned from interrogating a Traitor Astartes prisoner who revealed that he knew about Traitor Space Marines the Dark Angels had captured and now kept up on the Rock. Draigo was well aware that the Dark Angels would go to great lengths to protect their secrets and although he was unaware of the reasons why they would have such a vested interest in those imprisoned beneath the Rock he could still make an informed guess as to the nature of those secrets. It was not the possible knowledge of the Fallen that had motivated Azrael and his chapter, but rather the Grey Knight's knowledge of the methods employed by the Dark Angels to keep their secrets hidden, that ultimately ensured they honoured the ancient pact struck with the Grey Knights. And so the leader of the Dark Angels committed his entire Chapter to the Pandorax campaign, operational superiority the Grey Knight’s sole concession in exchange for cooperation. Though they were nominally allies, the relationship between the two Chapters had always been fractious, never spilling over into confrontation but coming near on more than one occasion. Being forced to operate so closely together would put that to the test once again, more so in light of the circumstances of their alliance. Several times in the book, Draigo warns Azrael that the Dark Angels will not interfere in his operations, or he will go straight to the High Lords of Terra and tell the High Lords about what the Dark Angels are doing. The threat is so real that Azrael commits the entire Dark Angels chapter (over nine hundred Astartes and nearly one hundred Neophyte Scouts) to the threat.
Of course, the whole issue with the Fallen was partly the Grey Knight's fault anyway; way back in the Horus Heresy, Garviel Loken & Half-Heard Cruze were sent to Caliban by Malcador to see where the Dark Angels' loyalties lay, but ended up getting captured and interrogated by Luther. Though it was clear the Fallen were absolutely clueless that the whole galaxy was at war around them, they were starting to be influenced by dark forces. Eventually, they were freed by these guys along with that one guy who was different from the other Fallen but managed to cause a fuss and kill someone, upsetting the fragile balance of ignorance that the lone warrior had been trying to maintain and tipping the Fallen over the edge. So while they could go back home and act as if nothing had happened and found the spotless Grey Knights, the Dark Angels came back and found their whole planet extremely pissed off and have to spend the next ten thousand years clearing up Qruze's mess. Loken actually castigated Qruze on the spot for the damage his killing of a Dark Angel might do, but doubtless he never suspected just how bad it would be.
So yes, the Grey Knights "should" already be aware of the touchy history of Caliban, but for all intents and purposes, they don't care or haven't actually figured out what it all means yet. Kaldor Draigo never actually claimed to know about the Fallen or about what happened on Caliban. In fact at the end of the Pandorax campaign, Draigo is seen screaming in Azrael's face demanding to know who these mysterious prisoners are and why the Dark Angels are so interested in them. Though to Azrael's credit, he actually doesn't have a clue why Draigo is so upset, since the Dark Angels didn't actually know about the particular Fallen Angel in question, who turned out to be an original Grey Knight Founder and was kidnapped by Abaddon instead.
At the end of the day (or the Imperium, as fluff would have it) it's hilarious. In a grimdark laugh-or-you'll-cry sort of way. But also almost justified, as the Inquisition have ex-communicated chapters for less before.
Who knows what?
At the close of the 41st Millennium, the Changeling managed to worm its way on to the Rock and unleash some prisoners, nearly reaching Luther's own cell before being repelled by one of the Watchers in the Dark, then was later banished by Azrael, Ragnar Blackmane, and Arvann Stern. Though the prisoners and their specific natures were not seen by the outsiders, parts of the dungeons were, though the Grey Knights knew about them anyway. The fact that several prisoners escaped no doubt set the Dark Angel's Hunt back several centuries at the very least, considering how rare it is to capture one of them.
With the current state of the Imperium, members of the Fallen have been publicly outed by appearing on Terra in the company of a freshly reborn Roboute Guilliman and would have been viewed (marching alongside the Grey Knights no less) by the teeming masses of humanity. Though what this means is mostly a matter for conjecture, since very few people ever get to see Space Marines in the flesh and not be destroyed by them that they might have just assumed they were normal Dark Angels wearing black. In any case, without specific knowledge of the Fallen (or the Grey Knights for that matter) the space marines in the company of the first Primarch the Imperium has seen in about eight thousand years would probably have been relegated to a side-show or a curious talking point.
More significant is the fact that said Fallen Angels were arrested by the Adeptus Custodes on the orders of Guilliman at the arrival to the doors of the throne room, and were placed in a Custodian prison that no-one had ever escaped from, though Cypher escapes in the following sentence. These prisoners would undoubtedly have tales to tell, though over a hundred years later, nothing seems to have come of it, and the Dark Angels were reinforced with Primaris Marines in the Ultima Founding, new Chapters were raised using their Gene-Seed, and they were permitted to keep their Deathwing and Ravenwing formations after petitioning Guilliman himself.
So the question becomes, who knows what?
So far we know:
- The High Lords of Terra have long believed that the Dark Angels were guilty of Legion-Building, but are unaware of the reasons. Hence why they were reticent to utilise their gene-seed in new Foundings despite their relative genetic purity.
- The Grey Knights knew the Dark Angels were taking prisoners back to the Rock, but were unaware of who they were, but agreed to keep this knowledge from the High Lords as a condition of Azrael accompanying the Grey Knights on the Pandorax campaign. However, the Grey Knights were seemingly unaware of any cooperation between the Unforgiven Chapters and found their close-knit way of speaking about each other odd.
- The Black Templars captured a prisoner and transferred him over to the Dark Angels at gunpoint. Those Black Templars were never seen again, though that incident may have been retconned.
- Thanks to the Fenris campaign and the four way parlay (Dark Angels, Space Wolves, Grey Knights, Inquisition) taking place on the Rock, the Inquisition now has members embedded throughout the fleet of the Dark Angels. Even if they don't have access to the deeper levels, the cells or the libraries, it does mean that they can monitor fleet movements and activities from now on.
- The Inquisition is also aware that a former Dark Angel: Vortigern was once a high-ranking member of the Black Legion.
- The Adeptus Custodes have Guilliman's prisoners under lock-and-key. Although their track record for gauging loyalty is spotty at best (they did imprison the Crusader Host and not manage to sort out their loyalties all that quickly, though a Blood Angel and Iron Hand were set free) and tend to take a "you're all a threat" approach. Though it probably is still only a matter of time before at least one of the Fallen opens his mouth and tells his story, though considering that the Fallen are generally not consistent with their stories, whether anyone believes him becomes another issue, though it would certainly raise suspicions and probably prompt investigation.
- Guilliman has had direct contact with Cypher, knows that he carries the Lion's sword, and knows he desires to meet the Emperor face-to-face. Guilliman is also one of the few living beings with first hand knowledge of the Lion and the Dark Angels pre-, mid- and post-heresy, so will already have no reason to believe any Fallen claiming that "the Lion was a traitor". (Hell, one of the Horus Heresy books has Lion kneel and beg to Guilliman for help in granting the Emperor the highest chance of survival; as far as Guilliman is concerned, the Fallen are outright delusional)
It could be said that if they all sat down together, they could probably figure out what was going on. Though the different agencies of the Imperium don't tend to have a habit of sharing information, various individuals might have an idea of what's going on, but not the whole picture. Since the Dark Angels typically don't leave witnesses to their actions there isn't much hard evidence to be laid down at their feet other than some hearsay, rumour and a few wrecked planets where they purged some "heretics" wink wink. This is probably not helped by the fact the Cypher managed to delete the Imperium's incriminating records on the chapter in mid M38, meaning the Imperium's ability to use hindsight has been massively curtailed.
Complicating things further still is the discovery that Luther himself has escaped his cell following an attack by the Fallen Angel turned Daemon Prince Marbas on the Rock. Azrael believes that he is planning to re-create his old Legion and has linked him to rumors of a massive gathering of Fallen somewhere in the Imperium Nihilus.
In Gathering Storm: Rise of the Primarch there are new rules for the fallen, Cypher and new missions and tactical objectives for playing them against loyalists. This book also encourages combining mark IV Space Marines, Dark Angel upgrades and Dark Angel Veterans to convert Fallen.
|Forces of the Fallen|
|Command:||Cypher - Fallen Champion|
|Allies:|| Chaos Space Marines |
Space Marines (Dark Angels Exempted)