WILL LION EL'JONSON TELL GUILLIMAN THE TRUTH? THE FATE OF CALIBAN 

I think when the Lion and Guilliman finally reunite, they're both going to realize that neither brother is quite the same person from ten thousand years ago. Guilliman has become quietly bitter, disillusioned, quick to anger, secretive, and extreme in his efforts to combat Chaos. He's also become slightly paranoid with keeping his plans and dealings hidden from virtually every major faction within the Imperium. On the plus side, he's also mellowed out when it comes to rule following. He's even bent his own rules in order to get things done. The Lion has become more open, more restrained with his temper, and actually considers potential consequences before acting. In short, the ambitious warrior statesman and the proud knight have been replaced by a tired, worn regent bearing a mantle he never sought, and an old warrior king battered by regret. I believe this element might make it easier for the Lion to open up to Guilliman about what really happened to Caliban and the existence of the Fallen. Both now have their secrets, and both have deep, personal regrets.

Guilliman: "Where did you disappear to after the Siege? I needed your help." Lion: "I had a slight disagreement with my sons..." Guilliman: "Also, where is Caliban, scans say it isn't there anymore?" Lion: "I had a slight disagreement with my sons..."

Um. Guilliman knows there were loyalists in the Iron Warriors and traitors in the White Scars. He gets nuance and mitigating circumstances. Plus he’s a pragmatist.

I just want to see Bobby G say “by the way, I saw your old sword, carried by a guy in black armor and calling himself Cypher.”

Guliliman might be a little surprised, but would shake it off and do what he could to salvage the relationship with his big brother for the survival of the imperium and humanity

Or did Gulliman deduce has happened to the Dark Angels on his own? Gulliman is a primarch and probably one of the most analytical characters in 40k. Did he interact with Cypher on Tera?

“Brother, can you keep the Fallen a secret?” “Can you keep my relationship with Yvraine a secret?” “Deal” “Deal”

The Lion: Look brother I blew up my home world because.... Guiliman: Who cares.... This Imperium is much worse any way and Jaggy had much more traitors...

Lion: The planet exploded from chaos Rowboat: Do you have any idea how little that narrows it down?

Imho The Lion never would have hid it from The Emperor in the first place. If he hadn't been incapacitated he would have handled his business in house and then immediately gone to tell the Emperor ( who was still somewhat able to be communicated with for centuries after interment) and let him decide if the Imperium as a whole should know he had fallen Marines and purged them like some other loyalist legions or if it needed to be buried so deep even Tzeentch couldn't find it. As for what he does now I think he has to come clean to Guilliman because they need to deal with whatever the aftermath of Arks of Omen is going to be.

Legend tells of the Lion berating Russ for this failings after the siege of terra. Failing to stay by the emperors side. Failing to kill Horus. And failing to return for the final Battle to protect the Emperor. All the same failings that the lion himself has.

We need more stories and lore on the 42M Lion. A problem with a lot of videos like this is we are honestly just spitballing, and the majority of what we know is old news from the 30K era that might not even be pertinent anymore. Honestly surprised there isn't more of 40K Lion already.

I'd love for Gman to already know via Cawl and not care cause he has far bigger issues to worry about.

I think he would unless it'd lead to the destruction of his legion. It's more likely that he'll keep shut with what the dark angels current actions to save them from the consequences of what they've done. I think he'll feel like it's his burden to carry because of the secrecy was what he left his legion

In truth I don't think Gilman would give a s*** one way or another. And he definitely takes that in about what happened to caliban and some of the others.

I don't think that the Lion will keep the Fallen a secret from Guilliman. But I also don't think that's the same as volunteering that information. As far as the Lion is concerned, his sons are his responsibility, and he is handling the matter. The past is, and should remain, the past. If Guilliman asks about it, I think that the Lion will tell him. But only if Guilliman asks. So the better question would be: does Guilliman already know enough TO ask? EDIT: I completely forgot about Guilliman knowing about Cypher. Yeah, this could come up.

Regardless of the secret being leaked on not.... all I want the reunification to mimic their meeting in the unremembered empire. It would be happy times.

Guilliman is already dealing with the Ecclesiarchy and high lords who were plotting against him. He needs allies so he can right the imperium and he has gone to great lengths to do so. I believe he will try his best to keep the Lion on good terms as he needs allies and as we all know Gman will already be devising plans for how to deal with all traitors/defilers when the time comes

It's a BIG if, but if El' Johnson does tell Guilliman he would say. "I understand, but we must not speak of this again. The Inquisition would have all your sons, your risen and those that hunted them put to death. It could break our father's crumbling Imperium. This Brother, is a secret we shall both keep."

As a Dark Angels fan from my childhood days, I hope ELJ tells Bobby G. Bobby G isn't an idiot, and he'll figure it out eventually now that he's back and sniffing corruption out. Why not gain the trust and admiration of one of the few souls who can counter your might in the Emperium? Also, 10,000 years is a long time. I'm sure they've both grown up. I'm sure they both realize that, as remaining brothers, they must stand with each other; after all, that's how their full strength will be reached. FOR THE GLORY OF THE EMPEROR!

I think Guilliman knows already. Most of the loyalist bloodlines have had some instance of individuals or chapters falling to chaos. keep in mind the lion is probably seeing this all through a lense where the HH is still fresh and recent. Guilliman is seeing it with 41st eyes.

GUILILIMAN may already know! Consider this, he was pulled on the threads of a puzzle for a long time, there is ample evidence that Dark angels has a history of suddenly disappearing mid task like a kitten chasing a Lazer. It's not hard to figure out what that something would be over 10000 years. Guililiman, could have figured it out, puzzled out the why, and is just waiting to see if the Lion will level with him with trust and honestly. Especially, since it doesn't matter other th a n the Lions pride is stained. Every Legion had members fall.

Johnson's legion didn't betray the Emperor. Johnson's legion betrayed Johnson because Johnson was half-stepping getting to Terra to help the Emperor.

I hope the Inquisition comes after the Dark Angels. Mainly because I am hoping it will somehow continue the Sons of Dorn and Russ vs Inquisition story line.

Hows Guilliman going to react to the fact that Johnson can 'forest walk' across the galaxy, seemingly teleporting from place to place in an instant. It sort of makes Lionel Johnson overpowered, as how many forces can just pop in and out of just about anywhere?

I think g-man knows but he will wait to see if the lion tells him. Wouldn't be surprised if he blames caliban on a select few traitors and it scattered his sons when they broke caliban and he's reuniting them

Girlyman is acting in the Emperors stead. I believe he would tell the Emperor, I would be surprised if he withheld this; for girlyman can't sacrifice the loyal and risk them also turn traitor. The lie will live on, the first never fell.

I think he tells Roboute but maybe the more important question is what happens with the gene seed? What is the threshold for considering the seed to be viable for future primaris?

I believe that this exchange will go down like this: - "Okay, a bunch of my sons betrayed me and I redeemed some. But I need to follow up on the rest of them." - "Oh. Okay." - "Wait, that's _all_ you have to say?" - "Brother, I've seen how many Space Marines turned against humanity. Most of them from _my_ geneseed. Why do you think this is such a big deal?" (Meanwhile, at GW.) "Oh, crap. We gotta make real non-retarded storylines for the Dark Angels now! What do we do!?"

Considering half of their brothers fell to chaos I don't think Guilliam can throw any stones.

I'd love if they just started doing oldman shit. Nodding off in chairs, complaining about their primarch sciatica, ect. Lion: "Some of my sons betrayed me" Guilliman: "What?!" *cups ear* Lion: "I SAID SOME OF MY SONS BETRAYED ME" Guilliman: "SANGUINIUS IS A DAISY?.. No no noo he was a bird remember?"

I so look forward to their conversation, both having an idea about what the other one hides: Lions fallen and Guillmans own imperium. Lion: Hey, bro. You got anything you wanna tell me? Guillman: No, you? Lion: Nope, nothing here either.

Is Guilliman going tell Lion how he had Cawl create thousands upon thousands of primaris marines from ultramarine geneseed more than any other thus making his own sons the most numerable marines in the imperium by a huge margin ? He already got accused of creating his own legion in the Dark Imperium books. Also regarding the inquisition coming for dark angels. What will they do ? Not only Lion uniting the unforgiven chapters and unleashing the full power of his legion will be more than enough to deal with inquisition even without inquisition hating chapters such as space wolves joining the party. But there is also absolutely no way Guilliman would turn against his brother because some of dark angles went rouge. Guilliman has no love for inquisition, ecclesiarchy and the imperial cult. He can't dismantle them on his own but he won't turn on a loyal brother.

Gman probably knows .. Cypher and him had a long talk with a specific sword that Guilliman broke present

Wouldn't Guiliman already know that's something weird is going on with the Dark Angels thanks to his dealings with Cypher? He, and several Fallen, did accompany Guilliman to Terra after all so at the very least, Roboute knows about the Fallen.

Maybe it's just me, but... why does it matter? Why would Guilliman care or give it a single thought, especially given the current events in the setting?

Turning the tables, how would the Lion react if he sees GMan with Yvraine.......

You can’t forget the mistakes of the current inner circle in the legacy of caliban omnibus, they messed up pretty bad.

I would love to see them hug when they finaly see one another

The First Legion never had traitors in its ranks, and never will. Nothing to tell here. The First will be risen again. ;)

the imperium at large can never know, it would be the death of the dark angels chapter and all their successors. i like to think the lion will tell roboute but i doubt he will. the converstation would likely be a case of not telling him because he doesnt need to know, or itll be the lion, all choked up and trying to confess it in a show of brotherly trust or whatever and roboute will just say "i know". and itll be left there. no need to actually say it, he knows, understands and forgives it all. maybe the emperor told him, maybe he worked it out for himself. the big blue would definately forgive him either way.

From the business side, I think GW is going to put it all out there between the Lion and Bobby G because they are using the Lion's return to fix what has become a dumb storyline. It was cool 20 years ago and 100 less books but now that everything is so much more fleshed out it just seems silly. They had a chance to fix space vampires and werewolve with Primaris and didn't do it. I don't think they'll make that mistake again. The Dark Angels as a more Arthurian flavor seems like it has more longterm legs.

In short ... no ... he will keep it as a secret... ;3

If the Lion blames it all on Alpha Legion then Gulliman will just shrug his shoulders and say ' thats okay'.

Can you imagine a totally honest reunion between them? The Lion : have you taken command of the entire Imperium against the very rules that you enforced on us all 10,000 years ago?? Guilleman: Did have your legion turn traitor? Awkward silence. 😂

I think Gulliman already knows. He isn't stupid and would notice all the changes to the other legions. Let's not forget tha Roboute has an equally dangerous secret in his formation of Imperium Secondus. The revelation of that would brand all Ultramarines as traitors. Lots of the Primarchs reactions have been miswritten. Roboute would be able to recognize legions from fallen brothers and other Primarchs. Little to no attention has been given to this. A story where Gulliman has to work together with legionaries from a traitor bloodline would make for a very compelling story. The writing has been blind to these things and tells stories as if the most observant and analytical primarch is clueless.

We need Vulkan to intermediate in these disputes. Or best Sanguinius

I think the lion can’t really hide it as I think Dante and the blood angels have pretty much figured it out anyway. I mean his personal retinue “ the risen “ a bunch of dark angels that none of the current blood angels know. Plus Robute has already had an interaction with Cypher so I think that cat’s out the bag if he doesn’t already know the truth then he has bloody whopping suspicions. Also don’t forget that old Robby already has experience of Johnny boy being a tad economical with the truth with that whole Kurze landing on Ultramar incident lol 😂

The points you make about the inquisition etc does make me think, much how Dante has become gullimans number 2, I feel that Logan grimnar of the space wolves will become the lions second

If Guilliman directly asks "Hey Lion, did half your legion turn traitor and cause you to blow up your own planet?" then The Lion may answer honestly. On the other hand if he doesn't ask that question then The Lion will just keep quiet. No need to actually lie if you're not even asked.

The truth? The Lion doesn’t know what happened on Caliban : He didn’t gave orders to exterminate the Planet. The only one that knows the truth is Cypher, who was on Board the Dark Angels armada comming back from Terra. Both primarch will e relief: they won’t be alone anymore.

"My homeworld was tough as it but it became a traveling hell planet" yea Roboogie would have sum questions if he discovers it

Honestly, could you speak a little more quickly? I have to put you on 1.5 speed for your intelligent drawl to become interesting.

...it all comes down to a trade. Guilliman accepts the secret, but Lion will tolerate Guilliman's preferrence for Aeldarian Dairy Products. Guilliman will tolerate Lion's preferrence for Celestial Divine, Sanctioned Mammary Produce. Azrael will have to share his foei grás w/ Zahariel. The Rock's nightclub will re-open, w/ franchises in Hera. And Asmodai will take anger management classes w/ *_HIM, CATO SICARIUS._*

He will not only reveal the secret of the fallen, but also admit that he has been married to Fulgrim for the past 8000 years, and they are planning to start their own interior decorating business.

The Inquisition declaring all-out war on the Lion and the Dark Angels because they found out some DA turned traitor 10k years ago would be the kind of peak Grim Derp nonsense that this universe has 'mostly' avoided in modern times. That kind of attitude is a relic of the old style of 40k lore that was very much an extremely clumsy and overwrought satire of religion, where Inquisitors would casually sentence entire planetary populations to death because someone mispronounced the name of a Saint. It was neither clever nor funny and is not missed.

Guilliman:"the past is the past, what matters is the future" Russ: "hahahahahahaha oh hahahahahahahahahaha, oh my all farther hahahahahahahahahahahahahahahahaha" Corax: "please note, if I see any hint of chaos filth, I will purge every single. one. of. your.marines." Clongrim: "...really I have no leg to stand on" Khan: "why should I care?" Dorn: "did you kill all the traitors? if so then move on, if not you have work to do." Dante: "it nice your telling me this...But why are telling me this?" Valdor: "are you stupid? are you fucking dumb? how could you let this even happen? why would you let this happen? are you braindead? this is the most dumbest thing I have ever heard and Dorn charged into a meat grinder!!!!"

Whaddya talking about? Individual Astartes may turn traitor, but the legion doesn't become traitor until their Primarch falls to Chaos. That didn't happen to the Lion. There is no reason for him to be afraid of telling the truth. "Long time, no see, Lion. What have you been up to?" "Rooting out traitors in our ranks." "Tell me about it."

From a strictly tactical standpoint, no biggie. DA, BA, and UM all made for Terra through the Ruinstorm. BA made directly for Terra, DA and UM tried crashing Horus' blockades. As others have noted, Corswain and some DAs made it to Terra and recaptured the Astronomican. The Lion destroyed traitor homeworlds in an effort to draw forces away from Terra... they were too far to make any direct impact on Terra so did what they could. AFTER the Siege and when they went back to Caliban is when Luther et al. turned. Not like other legions didn't have folks swap sides during the Heresy. Pretty decent record for the Legion still; they even destroyed their own homeworld to rout the Ruinous Powers. /shrug

Girlyman would understandnbut the lion couldnt stand the shame of others knowing.

GW has made it very clear the lion has changed. He is playing the role of a PROTECTOR NOW, first and foremost, and that will be his character arc. He will be transparent about everything.

I think with all the problems Gilliman is handling right now his reaction would probably be " Brother, for Emperor sake, it's been 10 thousand years. nobody even knows what really happened back then, except for the glorious banana boys behind you. and they really don't care. So please be a good sport and go unalive some demons or something! Also please drop by to see Pops, he would "appreciate" that!'

Should the Dark Angels’ Secret be revealed, that could open up the possibility of a similar revelation and rejoining of the Imperium by elements of the XX Legion

Except for maybe Russ or Sanguinus all the good primarch are written like pathetic spineless weaklings with PTSD, the only ones that seem to have balls turned to chaos. The writing gets worse and worse they probably should have all stayed dead or missing. The sisters of battle have bigger balls than Robute Girlyman, sad..... Lol

All joking aside and regardless of what comes after. Once all the public stuff is done and the two are finally alone together. I imagine the first words out of Lion's mouth will be. "You look tired, brother." To which Guilliman will have a small mental breakdown.

new to 40k here, but why is it necessary for Lion to withhold knowledge of the Fallen from Guilliman? Traitor legions aren't something new to the latter, so the knowledge of traitor DA shouldn't be shocking; unless this is more of a pride/ego thing for the Lion.

Theory time. I think Guilliman already knows. Hes been awake longer and been on a crusade. You're telling me he hasn't come across a Fallen squad? Also he's worked with Cypher. Most likely talked with him and knows what's going on. Finally, he's talked with Big E. More than likely, Guilliman has been told who is and is no longer loyal. I believe Johnson will tell him, fearing what Guilliman will think, only for him to tell Johnson, he already knew. Might be some brotherly bonding and so on lol.

He should tell him the truth, and then we will know the lion has finally grown up. All the lion fanboys constantly Tell me how he’s the greatest general by far, Then I mention the greatest losses in imperial history were because of him and his ego, and him thinking he’s smarter than he is. He literally killed the successful imperium by not telling his loyal brothers what was going on and telling Perty about his secret weapons, handing chaos a massacre and weakening the imperium for the next hundred years, not to mention wiping out three legions of loyals. He was responsible for chaos reaching earth, countless worlds falling, because there was no one left to slow them down. He was always a bad judge of character, trusting people like Luther, but he compounded it by being suspicious, and suspecting G-man while literally empowering the actual traitors. If he would’ve included G-man, they both could’ve set a trap and literally ended chaos right there. The white scars and salamanders and iron hands would be alive as well as sanguineous, because Horace would’ve been defeated in his first major battle. Chaos would’ve been killed in its crib. I’m hoping that the lion really has changed and is no longer the egomaniac who thinks he’s smarter than G-man, who has actually proven to be the greatest general and greatest Primark (as long as he doesn’t use his personal feelings. Like he did with Fulgrim) The truth is the lion didn’t like anyone he perceived, as better than him or a threat to him in skills… The lion said himself if G-man fell to chaos he would be the ultimate threat even worse than Horace, because G-man always held back because of morals. But as far as tactical ability and sheer mental bandwidth, G-man is an AI super computer far beyond any living being outside of the Necrons. G-man never makes the same mistake twice, learns at 10 X, the rate of other Primarks, and unlike the fan Boys want people to think had by far the best military education and formal training of Any Primark… while the lion was hunting, chaos monsters with a few hundred knights, g-man was being trained by the best military tutors in all of Ultramar, which already had the best soldiers. He mastered every single weapon class, and at 16 had more military experience in command experience than anyone. People just rebel against G-man because GW pushed him so hard. But the reality is all the Primark are physically perfect, so what separates them is their ““ superpowers. Most of the Primark are the best at one thing in the entire universe but this makes them weak in other areas. G-man and his superpower is unlimited learning and unlimited potential. so while he’s not better at the other Primark’s best skill, his second or third best in every single category, and has the ability to learn how to become the best. His only drawback was, he was naïve and gullible. he always saw the best and was over trusting. With the Lions natural suspicion and the fact that they can now love each other rather than compete, G-man and him could make a perfect team.

I do think the Lion will tell Guilliman. Many have said this perfectly well already but both are changed men. Not entirely for the better in some ways but, in ways that I really do believe will help them put aside past issues and truly be brothers. Even if for no other reason than that they both are smart enough to know that true unity and trust is what is needed to save humanity and the time for anything less is over. Besides, at the end of the day, I think that finally meeting each other will bring up enough feelings of joy - in the simple fact that they are not alone in this galaxy wide disaster - will mitigate a LOT of potential issues between them. Especially on Guilliman's side. I'd even be willing to believe that Guilliman would be so overhoyed to see another loyal brother (ANY brother) returned that he frankly couldn't give a shit about the Fallen - especially considering that Gulliman of ALL people KNOWS that rhe Lion's own loyalty is so utterly beyond question. If the Lion tells Guilliman about the Fallen and his plan to gather those still loyal while purging the traitors, no matter what else Gulliman might think, he will KNOW that those the Lion redeems are loyal and no risk to the Imperium - because if there was even a HINT of traitor in them, the Lion would have killed them on the spot.

I think Guilliman would be understanding. He and the Lion have changed over these 10k years, bot to mention, Guilliman has worked with loyalist elements of traitor legion, notably Barabas Dantioch and his men.

Guilliman : How is that homosexual nightclub in your basement going? Lion: How do you....?

Wolf Lord Rho, how do you know that I didn't Tell my Son about the truth about the Dark Angles?- The God Emperor

There isnt really any reason for Lion not to tell Guilliman, it's not like he'd be announcing it to the whole Imperium, there's nothing to loose by telling Guilliman the truth and everything to gain in building a repour. There's also no reason for Guilliman to judge the Lion, nothing that's happened since Calibans fall can be blamed on him because he wasnt around and he didnt leave by choice. There's no reason to judge him for what happened on Caliban because Luther being corrupted by Chaos, supressing any attempts to make contact beyond Caliban and supressing any attempts to put an end to Luthers plans, eventually resulting in Luther convincing his men that the Lion had turned on them, was not his fault, and much of that picture can be supported by the Fallen who've joined the Lion and personally knew varying amounts, but also learned over the course of "Lion Son of the Forest", that Luther started and staged the whole thing. So yea, when they meet, Lion should be open about what he knows and what he's been through, and Guilliman should be overjoyed to have a brother back but also to see the Lion so matured, I honestly wouldnt be surprised if Guilliman admired him even more now, at least on a personal level. Especially given that Lion has generally changed for the better after all he's been through. I also think it would make sense for the Lion to be a bit of a big brother for Guilliman because, while Guilliman has matured somewhat in a way Lion will appreciate, he's also gone through a lot that would benefit from some comradery.

30k and 40k Lion are almost two different people. 40k Lion is more reasonable and even have some people skills, so I think he would tell Guiliman everything.

Older wiser clear vision now, "I took care the problem with my sons, Lets see Pops" oh and if Malchy's Inquisitors want to visit, there is a airlock ready for them if they have problems :)

I think the fact that Guilliman could replace the angels with primaria weighs in on it and Guilliman may want to know what the angels have done to keep the secret

Bobby g: I know it took great courage to tell me brother. I also have a dark secert. Lionel: Oh, it can't be any worse than what i told you. Booby G: Well.... I want you to meet a elder woman...

Not only will Lionel Johnson tell girly boy girly boy is going to look his brother in the face. Put his hand on his shoulder and then quote Han Solo "I know" Maybe even add a little more love by saying " brother, there shall be no empty plinths in our Imperium"

Every legion had traitor elements. The Dark Angels are extremely arrogant for not admitting to theirs, but I don't see why the Lion wouldn't.

i dont mind tension but i hope it does not become a drama fest and we get lion and Guilliman acting like children bitching and moaning and fighting over stupid stuff. Just, let them be smart, im sick of "smart people" always doing stupid shit. Let them learn from 30k.

I don’t think he will lie, I just don’t think he will bring it up. If asked he would tell the truth but I think in his mind he is dealing with it so why speak of it.

Gets me how no fallen have been found by any other legions by now. Why has no fallen tried to contract other legions, or Terra? I mean they have to have some clue of what is going on around the galaxy. Or were they just randomly spread out on backwater worlds with no communications or space travel.

In my head canon Bobby G already knows but he will use it as a test to determine how trustworthy Lion is. If Lion doesnt say anything, it will lead G to distrust him, if Lion comes clean without prompting, they'll deal with it together.

Johnson keeping the secret if Caliban would take such utter, such sheer narcissism that the Lion may just implode

Let’s be honest. His was more failed communication for most of the fallen. Every legion had a traitor sect, his wasn’t awful.

I just wonder what is the importance that the first fallen he meet is a uncrowned prince Zabriel. And Zabriel was hand crafted by the Emperor himself.

I think as soon as the Lion and G-Man get in a room together privately, the Lion will see the strain of carrying the Imperium on Guillimans face and immediately realise he was wrong about him from the start.

When Dorn and Constantine return along with the black Templars they will purge the inquisition

I don't think its that important, Roboute has probably guessed most of it but doesn't know the details which are not that important apart from where he was and how he came back and who the enemies are, will they work together and how etc It happened 10 000 years ago and Roboute was present so it won't be surprise even if he does tell him.

I think he'll start to tell him, and Bobbie G will finish his sentence. His agents may have already found out.

Lion: you broke up my legion!!! Rowboat: maybe if you didnt get dunked on by a planetary garrison youd have had a say

A Brothers love is a brothers love....unless you hear the word 'Dreadwing' then its new underwear times....

I expect the lion to finally say it.. and Guilliman just says... "ok. Sure. Shocking a legion had some traitors but most stayed loyal.. crazy.. dont care. I need your help with retaking and fixing this shit show we call the imperium"

Son of the forest told that the lion had regrets about not trusting guilliman from the start.

it's the Lion so the answer to your question at the start is no, especially knowing the Lion this will comeback to haunt him and break any good standings with Gorillaman.

A Dark Angel admit the truth....What drugs are you on wolf and can I have some?

You are forgetting that Cypher met Roboute before. Maybe Roboute already knows

Thing is could guilliman already know about the fallen as he was rescued from the red corsairs by cypher and travelled to terra with him who knows what was revealed

He needs Guilliman as an ally more than ever….he isn’t going to risk distrust by prevaricating

I do think Lion should tell RG about his legions traitors and trust RG to decide to tell basically no one else about this because so much of the IOM is black or white and no gray.