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I just made this epic discovery, and felt the need to share it. In the new Horus Heresy novel, Age of Darkness (spoilers ahead) one of the short stories is called Rebirth, taking place from a Thousand Son's Captain and his squad. Eventually, through much action, one soldier is left, a Corvaede (spelling?), part of the legion whose psychic power is the ability to see into the future. He becomes aware of what his future is, which is to reunite the remnants of the Legion into a new fighting force to fight for the Emperor. In the end, the very last paragraph depicts the Corvaede's marking - a black raven (hence the chapter symbol). As the preheresy chapter colors were the same red of the Blood Ravens, this is the clear and official fluff to where the Blood Ravens had come from, and that this one thousand son's trooper created the Legion.

So it is true then, their Primarch is Magnus the Red.
Do the Inquisition knows about this?

Just got to wait for Kanluwen to come in now and say no no no, this isn't true

Hehe..
Let the Space Wolves not find out!

To Confirm and correct the OP, just found this on the lexicanum,

http://wh40k.lexicanum.com/wiki/Age_of_Darkness_%28Anthology%29#Rebirth
http://wh40k.lexicanum.com/wiki/Revuel_Arvida

Flesh Change.

That is all.

i tried explaining this a week or so ago in another forum and the people ignored it sighting things like flesh change and what not. magnus cured the flesh change....the only thousand sons that suffered from it were the ones trasported to the planet of sorcerers, so that doesnt disprove blood ravens being thousand sons. i think the books states it quite clearly they are

Brother Coa wrote:So it is true then, their Primarch is Magnus the Red.
Do the Inquisition knows about this?

Everything is so black and white to you.
This is interesting news...
It would be more interesting if the Inquisition knew about it and used it to control the Blood Ravens.
As it is it remains an interesting piece of trivia about them.

If the Blood Ravens were are part of the 21st Founding then it's possible that the geneseed was one that they had attempted to have the impurities removed. It's a big if as it is a Traitor geneseed.

If it is, it is quite possible that the Blood Ravens will still have the flesh change issue. But it just hasn't come into fruition yet. The Lamenters, for a long time, had stable geneseed and seemed to not suffer from the Black Rage and Red Thirst. But according to IA: Badab War are beginning to show signs.

I think it's a possible big nod that the Blood Ravens are Thousand Sons marines. But to have the Thousand Sons who survived find the truth and stay loyal, I am not sure that would happen.

purplefood wrote:

Brother Coa wrote:So it is true then, their Primarch is Magnus the Red.
Do the Inquisition knows about this?

Everything is so black and white to you.
This is interesting news...
It would be more interesting if the Inquisition knew about it and used it to control the Blood Ravens.
As it is it remains an interesting piece of trivia about them.

According to the Lexicanum quotes on the post up, it is. Beside it is the most logical thing, both of them are seeking knowledge. Only difference is one is loyal - other is not.
Black and White.

Sanguinius1385 wrote:i tried explaining this a week or so ago in another forum and the people ignored it sighting things like flesh change and what not. magnus cured the flesh change....the only thousand sons that suffered from it were the ones trasported to the planet of sorcerers, so that doesnt disprove blood ravens being thousand sons. i think the books states it quite clearly they are

Magnus did not cure the Flesh Change.

Without really getting into it, he made a deal to 'cure it', but when he reneged on the deal it was brought back fully by the one he made a deal with. If you want to know more, read "A Thousand Sons".

Ahriman tried to come up with a cure--but it turned those Thousand Sons afflicted by the Flesh Change into echoes of themselves, shadows trapped within their armor for eternity.

If anything, this seems like another attempt to just set up a possible 'origins' for the Blood Ravens.

But if it were true, then the Blood Ravens were created during/immediately after the Heresy and that doesn't sound right--at all.

Plus, as a sidenote, every member of the Corvidae Cult had that raven on their shoulderpad. This is not news.

They've got no blood drop in the center of the raven, thus they are not the Blood Ravens.


Automatically Appended Next Post:

Pilau Rice wrote:Just got to wait for Kanluwen to come in now and say no no no, this isn't true

Could it be true?

Maybe. But at the same time, it seems more and more like this is just to screw with people's theories.

We've got theories of them being descended from Horus, Magnus, Corax, Sanguinius, pretty much every Primarch.

Brother Coa wrote:

purplefood wrote:

Brother Coa wrote:So it is true then, their Primarch is Magnus the Red.
Do the Inquisition knows about this?

Everything is so black and white to you.
This is interesting news...
It would be more interesting if the Inquisition knew about it and used it to control the Blood Ravens.
As it is it remains an interesting piece of trivia about them.

According to the Lexicanum quotes on the post up, it is. Beside it is the most logical thing, both of them are seeking knowledge. Only difference is one is loyal - other is not.
Black and White.

Not what i mean Coa.
You assume that:
A)The Inquisition doesn't know about this
B)They would necessarily want to do anything about it
C)They didn't help the Captain create the Blood Ravens in the first place

Kanluwen wrote:
Maybe. But at the same time, it seems more and more like this is just to screw with people's theories.

We've got theories of them being descended from Horus, Magnus, Corax, Sanguinius, pretty much every Primarch.

But there is difference with this one. It's from the book: "Part of the fleet that was sent off before the Space Wolves attacked during the Burning of Prospero. He returned to Prospero a few months later to investigate the loss off communication with the legion. Upon arriving on the surface of Prospero, he and his team were ambushed by members of the World Eaters Legion. They fought their way back to the lander and got separated from the rest of the squad. It was surrounded by World Eaters and he was alone. So already being disgusted by what his Primarch had done, he disappeared into the night saying the words "Knowledge is Power" and the Symbol of the Raven's head shown on his shoulder."




Automatically Appended Next Post:

purplefood wrote:
Not what i mean Coa.
You assume that:
A)The Inquisition doesn't know about this
B)They would necessarily want to do anything about it
C)They didn't help the Captain create the Blood Ravens in the first place

Oh..sorry, having a lot on my head today...

Brother Coa wrote:

Kanluwen wrote:
Maybe. But at the same time, it seems more and more like this is just to screw with people's theories.

We've got theories of them being descended from Horus, Magnus, Corax, Sanguinius, pretty much every Primarch.

But there is difference with this one. It's from the book: "Part of the fleet that was sent off before the Space Wolves attacked during the Burning of Prospero. He returned to Prospero a few months later to investigate the loss off communication with the legion. Upon arriving on the surface of Prospero, he and his team were ambushed by members of the World Eaters Legion. They fought their way back to the lander and got separated from the rest of the squad. It was surrounded by World Eaters and he was alone. So already being disgusted by what his Primarch had done, he disappeared into the night saying the words "Knowledge is Power" and the Symbol of the Raven's head shown on his shoulder."

People need to get off of this train that "Knowledge is power" is something exclusive to the Blood Ravens and instantly means that there's a connection.

It's not. As of the Heresy books we've seen it in things from the Thousand Sons, Word Bearers, Dark Angels, Raven Guard, Night Lords, and Alpha Legion.

Hell, Malcador the Sigilite says it to Garro before he gives him the offer of starting the Inquisition.

Brother Coa wrote:

Kanluwen wrote:
Maybe. But at the same time, it seems more and more like this is just to screw with people's theories.

We've got theories of them being descended from Horus, Magnus, Corax, Sanguinius, pretty much every Primarch.

But there is difference with this one. It's from the book: "Part of the fleet that was sent off before the Space Wolves attacked during the Burning of Prospero. He returned to Prospero a few months later to investigate the loss off communication with the legion. Upon arriving on the surface of Prospero, he and his team were ambushed by members of the World Eaters Legion. They fought their way back to the lander and got separated from the rest of the squad. It was surrounded by World Eaters and he was alone. So already being disgusted by what his Primarch had done, he disappeared into the night saying the words "Knowledge is Power" and the Symbol of the Raven's head shown on his shoulder."

You are also quoting Lexicanum which is someone elses interpretation of what happened.

What is the specific quotation in the book?

Kanluwen wrote:
People need to get off of this train that "Knowledge is power" is something exclusive to the Blood Ravens and instantly means that there's a connection.

It's not. As of the Heresy books we've seen it in things from the Thousand Sons, Word Bearers, Dark Angels, Raven Guard, Night Lords, and Alpha Legion.

Hell, Malcador the Sigilite says it to Garro before he gives him the offer of starting the Inquisition.

Which is very true and I agree with you, it is a commonly said phrase throughout the Imperium.

But the Index Astartes: Blood Ravens specifies that their battle cry is Knowledge is Power, Guard it well. It's just another link to the Thousand Sons and Blood Ravens theory.

Here's the ending passage for "Rebirth".


Major spoiler warning. It's why I'm putting some dead space in here so that a spoiler won't accidentally bleed through in the thread preview.


This should be enough.


It honestly seems more to me that Arvida would go on to become a member of Garro's "Band of Inquisitive Nature" than becoming the founder of the Blood Ravens.

I agree with Kan.
The symbol is different as well.
Possible founder of the Ordo Malleus Inquistion.

Kanluwen wrote:Here's the ending passage for "Rebirth".


Major spoiler warning. It's why I'm putting some dead space in here so that a spoiler won't accidentally bleed through in the thread preview.


This should be enough.

Spoiler:

He would survive. He would discover the true causes of his Legion's destruction, and live to fight them. He would neither pause nor stumble until everything had been revealed to him, everything that would give him a weapon to employ.
'Knowledge is power,' he breathed.
Then he turned away from the scene, and stole quickly back into the occlusion of the ruins. As he went, the dim red light of the angry magma fires caught on his shoulder-guard, exposing the serpentine star set about the black raven-head of his cult discipline.
Then he was gone, a shadow among shadows.

It honestly seems more to me that Arvida would go on to become a member of Garro's "Band of Inquisitive Nature" than becoming the founder of the Blood Ravens.

Possible, but it just seems to all point in the direction of the Blood Ravens. It is very possible that this happened: Arvida goes off with Garro, and while he is with him, asks to form a legion of all the remaining loyalist thousand sons. I believe if asked, Garro would have said yes as he knew there were still loyalist marines alive, and willing to fight. So after a few hundred years of gathering the remnants,they are formed into a new chapter that goes off to fight. However, their history is wiped, because if the Blood Ravens found out that their true primarch was Magnus, it could start a mini heresy all over again, if they felt more loyal to their loved and lost primarch rather than the Emperor. It would be fitting, because, like what Garro and Qruze did to their armor, they would either destroy their colors and symbols, or, which seems to have happened, would be to add in new colors, and alter the symbol to make themselves look like a new legion.

This explains the basic stuff, like thirst for knowledge and large amount of psykers. However, as you said, the fleshchange could still happen. I believe that, as described in A Thousand Sons, if their powers are used in a very minor degree, there is a rare chance of it happening, and it only happens if their powers are too strongly used. I would think that they would try to suppress the change as much as possible. Also (spoilers) In rebirth, the World Eaters were there looking for a cure for their horrible rage issues. Is it not possible that the loyalist Thousand Sons too went back looking for a cure? It could also be a mirror of the World Eater's rage, and the thousand son's change, and how they both needed cures.

Edit: And as you just said in the other thread, it was a Raven's Skull. Is it not possible, to be used a literary device, to go from the bare bone of a skull, and grow into a full raven. Hence the growth of one Thousand Son into a brand new chapter?

Chapters don't change their livery willy nilly.

The Flesh Change, as described in "A Thousand Sons" always happened if they used their powers.

The Blood Ravens, as a whole, are not an entirely psychic Chapter. They have a propensity for fielding Librarians, but they do not have the psychic acumen the 1k Sons did.

So in short: unless GW pulls a rabbit out of their hat--it's not any Legion we have information on right now, and it most certainly is not a Traitor Legion--of which there's no way for anyone to get access to the geneseed.

It would make sense i guess
Although, when THQ made the blood ravens, i don't think they looked into the fluff that far.
Plus, aren't all thousand sons psykers?
The blood ravens may have several of them, but not every brother.

Its not willy-nilly, its trying to reform a new, loyalist chapter from a traitor legion

As for psykers, in my opinion, it could be like the original founding of all legions. The first few were from terra, but they were truly branched out by their Primarch's founding world. It could be that a few thousand sons made up the chapter, like the terrans, but once large enough, they broke off and started basic recruiting, with a primary focus on psykers.

Though i do agree, the fleshchange is something that leaves a rather large gap. Perhaps, like others said, they found a cure, but that seems unlikely because that aspect is completely left out.

elysiandroptrooper108 wrote:Its not willy-nilly, its trying to reform a new, loyalist chapter from a traitor legion

And that wouldn't have happened. The Death Guard, the Sons of Horus, the Emperor's Children, etc all had some form of "Loyalists" who made them up.

They didn't create a new 'Chapter' from those guys. You really heard nothing about them until the Garro storyline surfaced now.

Best bet is that "Rebirth" is hinting towards the formation of the Ordo Malleus and the Grey Knights. Which makes a perfect sense, considering the mention of "Nemesis"in "A Thousand Sons".

As for psykers, in my opinion, it could be like the original founding of all legions. The first few were from terra, but they were truly branched out by their Primarch's founding world. It could be that a few thousand sons made up the chapter, like the terrans, but once large enough, they broke off and started basic recruiting, with a primary focus on psykers.

Every member of the Thousand Sons was psychic to a rather large degree.
The problem is they weren't all talented in the same aspect. Some were more skilled at kinetic manipulation, others at conjuration, and still others at divination, etc.

Though i do agree, the fleshchange is something that leaves a rather large gap. Perhaps, like others said, they found a cure, but that seems unlikely because that aspect is completely left out.

The Flesh Change can't be cured. The only "cure" was a suppressing of it by a certain .

Kanluwen wrote:Chapters don't change their livery willy nilly.

The Flesh Change, as described in "A Thousand Sons" always happened if they used their powers.

The Blood Ravens, as a whole, are not an entirely psychic Chapter. They have a propensity for fielding Librarians, but they do not have the psychic acumen the 1k Sons did.

So in short: unless GW pulls a rabbit out of their hat--it's not any Legion we have information on right now, and it most certainly is not a Traitor Legion--of which there's no way for anyone to get access to the geneseed.

Chapters may not change their livery 'willy nilly', but after a major event - Primarch becoming Warmaster, finding your warmaster, going renegade, your entire legion turning to Chaos, and finding out your the last one loyal to the Imperium - changes can certainly occur.

As for the 'psychic acumen' of the 1k Sons, well, we aren't talking about an entire Legion. Now, we have a single Marine who's still loyal. A single Marine, placed as a Chapter Master, who came from a Legion of psykers is most likely going to encourage the use of psychic powers in the Chapter.

That being said, the idea of Arvida being one of the first Grey Knights is also a likely result.

Wouldn't their gene-seed be diluted and as a result the percentage of psykers would drop?
And the thousand sons would mutate if they used their powers beyond a certain level but before Magnus gave his eye this level was very low and was the same on the planet of the sorcerors

A Thousand Sons wrote:
"All told, twelve hunder and forty-two warriors survived the razing of prospero"
"It has become even more strife amongst our number, and seventy-two warriors have succumbed to the flesh change"

\that is not all of the 1k sons

infinite_array wrote:

Kanluwen wrote:Chapters don't change their livery willy nilly.

The Flesh Change, as described in "A Thousand Sons" always happened if they used their powers.

The Blood Ravens, as a whole, are not an entirely psychic Chapter. They have a propensity for fielding Librarians, but they do not have the psychic acumen the 1k Sons did.

So in short: unless GW pulls a rabbit out of their hat--it's not any Legion we have information on right now, and it most certainly is not a Traitor Legion--of which there's no way for anyone to get access to the geneseed.

Chapters may not change their livery 'willy nilly', but after a major event - Primarch becoming Warmaster, finding your warmaster, going renegade, your entire legion turning to Chaos, and finding out your the last one loyal to the Imperium - changes can certainly occur.

Without going into it too deeply:
He was still wearing the same heraldry as he wore in the 1k Sons.

As for the 'psychic acumen' of the 1k Sons, well, we aren't talking about an entire Legion. Now, we have a single Marine who's still loyal. A single Marine, placed as a Chapter Master, who came from a Legion of psykers is most likely going to encourage the use of psychic powers in the Chapter.

And yet, the Blood Ravens as a Chapter seemingly have no more Librarians than the Dark Angels or Ultramarines.

They just will field them as groups of Librarians and also have a Librarian in a bigger leadership role than normal.

Kanluwen wrote:
Without going into it too deeply:
He was still wearing the same heraldry as he wore in the 1k Sons.

Kanluwen wrote:
And yet, the Blood Ravens as a Chapter seemingly have no more Librarians than the Dark Angels or Ultramarines.
They just will field them as groups of Librarians and also have a Librarian in a bigger leadership role than normal.

1st. Sorry, I though you meant after the event of Rebirth, not during it.

2nd. The Blood Ravens have been known to have higher numbers of Librarians than other chapters. Other chapters will place a single Librarian into a Company when going into combat. The Raven's ability to field multiple Librarians, groups of Librarians, and give Librarians battlefield command roles seems to implicate not only a abnormally large number of Librarians within the chapter, but also a fundamental trust and prevalence on the importance of psychic powers.

Not only may they have higher numbers, but they also put them into command roles. In the horus heresy books, it was made very clear that almost every legion did not approve of the heavy use of psykers, as they believe them to be poor leaders, witches, and untrustworthy. Only the Thousand Sons and Blood Ravens have chapter masters, company commanders, and other high ranking officers as librarians.

Wow. This thread again. And the same old denials. Since we're arguing some points, I'll present all the supporting evidence again for completeness' sake.

As a general recap from the White Dwarf articles:
- Blood Ravens have a very high number of Librarians
- Blood Ravens are continually thirsting for knowledge, to the point that it's come many times to the Inquisition's notice
- Blood Ravens don't know their Primarch, just their Father Librarian
- Their history has been purposefully obscured
- One squad/company disappeared into the Eye of Terror, led by their Librarian, in search of knowledge

Revealed in Ascension
- Blood Ravens in the far, lost past built a recruiting world outpost on top of an earlier marine outpost for some reason
- This earlier marine outpost was built during the time of the Heresy. It was built by marines in Red Armor (Thousand Sons, Blood Angels, or Word Bearers).
- These marines were able to work with the Eldar to set magic and psychic wards to lock a Necron force in Psychic Stasis (I think this eliminates Blood Angels and Word Bearers)
- These Heresy Era marines were tasked by the Eldar with guarding this galaxy wide threat, but they mysteriously left abandoned the planet and it was never recorded again in Imperial records until the Blood Ravens took it back over
- Finally, the Eldar still remember working with the Red Heresy Era marines, and mistake the Blood Ravens as being one and the same

Revealed in Tempest
- The Blood Ravens can field entire squads of Librarians and even have a secret inner circle of Librarians sort of like the DA Deathwing, who hold knowledge not spread throughout the rest of the Chapter
- The Blood Ravens resent the Imperial Fists, and even have a secret tome written about the un-founding, explaining how those Founding chapters aren't necessarily all they're cracked up to be
- The Blood Ravens Father Librarian Vidya was known to Arhiman of the Thousand Sons
- Arhiman hints that the Blood Ravens Librarians' bear the same color as the T-Sons as more than a coincidence, it's based on the Rubric of Arhiman
- Ahriman is intimately familiar with the details of the founding of the Blood Ravens, but doesn't explain how
- Ahriman of the Thousand Sons, the Eldar and the Harlequins, and the Blood Ravens of old and their Father Librarian are all very linked in the ancient times

This is what we knew before the HH Novel.

A Thousand Sons
1) The Corvidae (Ahriman belongs to this Cult) are obviously named for Ravens, but additionally, its members actually have Ravens' Heads emblazoned on their shoulder pads. They are also the Guardians of the great Library.
2) The Possessed Remembrancer glimpes the future"...the lost sons and a Raven of Blood. They cry out for Salvation and Knowledge but it is denied?..."
3) Before the Wolves arrive for the seige, 4 Thousand Sons battle barges and their attendant Squadrons of strike cruisers are sent off in different directions so they cannot interfere in the Seige, with special sealed orders. We never learn the the orders, or who was on them.

Rebirth
1) The Thousand Sons not with the Legion on Prospero survived the flesh change. Not just the squad in the book, but the rest of the fleet they were with. It was lost in battle, not to the flesh change.
2) The Corvidae Sgt. survives to escape the planet, and is going to live to try and find out other survivors and the reasons for the Legion's destruction.
3) Sgt Arvida blames Magnus and his arrogance for whatever happened.
4) "Knowledge is Power" he says aloud, which is also Blood Ravens' motto.

You can argue individual points. You can choose to disregard Goto's books. But when it's all taken into account, there really is not room for doubt. GW is telling us the Blood Ravens are decended from the survivors of the Thousand Sons.

Would be funny if it was a mindf**k on epic proportions...

odmiller wrote:Wow. This thread again. And the same old denials. Since we're arguing some points, I'll present all the supporting evidence again for completeness' sake.

As a general recap from the White Dwarf articles:
- Blood Ravens have a very high number of Librarians
- Blood Ravens are continually thirsting for knowledge, to the point that it's come many times to the Inquisition's notice
- Blood Ravens don't know their Primarch, just their Father Librarian
- Their history has been purposefully obscured
- One squad/company disappeared into the Eye of Terror, led by their Librarian, in search of knowledge

-Many Chapters have high numbers of Librarians. Dark Angels have historically been a Chapter with a large amount of them.
-Many Chapters are "continually thirsting for knowledge". The Relictors come to mind, and they've been sanctioned by the Inquisition as well.
-Successor Chapters don't have Primarchs. Only the Founding Legions did, with many of the Successors from those Legions tracing their heritage from there.
-This is nothing special
-Again: nothing special.

Revealed in Ascension
- Blood Ravens in the far, lost past built a recruiting world outpost on top of an earlier marine outpost for some reason
- This earlier marine outpost was built during the time of the Heresy. It was built by marines in Red Armor (Thousand Sons, Blood Angels, or Word Bearers).
- These marines were able to work with the Eldar to set magic and psychic wards to lock a Necron force in Psychic Stasis (I think this eliminates Blood Angels and Word Bearers)
- These Heresy Era marines were tasked by the Eldar with guarding this galaxy wide threat, but they mysteriously left abandoned the planet and it was never recorded again in Imperial records until the Blood Ravens took it back over
- Finally, the Eldar still remember working with the Red Heresy Era marines, and mistake the Blood Ravens as being one and the same

Really? Uh, Word Bearers wore grey armor.

One specific branch of them had Red Armor.
Yeah. "Tasked by the Eldar" during the Heresy? Not happening.

Typical C.S. Goto failure at writing.

Revealed in Tempest
- The Blood Ravens can field entire squads of Librarians and even have a secret inner circle of Librarians sort of like the DA Deathwing, who hold knowledge not spread throughout the rest of the Chapter
- The Blood Ravens resent the Imperial Fists, and even have a secret tome written about the un-founding, explaining how those Founding chapters aren't necessarily all they're cracked up to be
- The Blood Ravens Father Librarian Vidya was known to Arhiman of the Thousand Sons
- Arhiman hints that the Blood Ravens Librarians' bear the same color as the T-Sons as more than a coincidence, it's based on the Rubric of Arhiman
- Ahriman is intimately familiar with the details of the founding of the Blood Ravens, but doesn't explain how
- Ahriman of the Thousand Sons, the Eldar and the Harlequins, and the Blood Ravens of old and their Father Librarian are all very linked in the ancient times

This is what we knew before the HH Novel.

I forgot to add this part.
-So what? Ahriman is intimately familiar with the Warp and various scrying and divination methods.
-ALL Librarians "bear the same color as the Thousand Sons". The Rubric of Ahriman has nothing to do with the color their armor turned.
-Again: Intimately familiar with the Warp and various forms of scrying/divination.
-The "Blood Ravens of old" could not have existed during the Horus Heresy.
Period. End of story.

A Thousand Sons
1) The Corvidae (Ahriman belongs to this Cult) are obviously named for Ravens, but additionally, its members actually have Ravens' Heads emblazoned on their shoulder pads. They are also the Guardians of the great Library.
2) The Possessed Remembrancer glimpes the future"...the lost sons and a Raven of Blood. They cry out for Salvation and Knowledge but it is denied?..."
3) Before the Wolves arrive for the seige, 4 Thousand Sons battle barges and their attendant Squadrons of strike cruisers are sent off in different directions so they cannot interfere in the Seige, with special sealed orders. We never learn the the orders, or who was on them.

1) And you know what else they were? Diviners and scryers who served as the eyes and ears of the Legion during war.
2)Quote the entire piece or don't quote it at all.

"It's too late...the Wolf is at the door and it hungers for blood. Oh, Throne...no, the blood! The Ravens, I see them too. The lost sons and a Raven of blood. They cry out for salvation and knowledge, but it is denied! A brother betrayed, a brother murdered. The worst mistake for the noblest reason! It cannot happen, but it must!"

This can almost literally mean anything.
Corax has a big thing going on where he begins tampering with genetics to create 'fastgrown' Astartes. They ended up as monsters, and he referred to them at one point as his "lost sons". They were intelligent, if beastly, and rather than being kept alive they were killed after the Heresy.
3) Of course we don't. Because this lets the conspiracy theories continue.

Rebirth
1) The Thousand Sons not with the Legion on Prospero survived the flesh change. Not just the squad in the book, but the rest of the fleet they were with. It was lost in battle, not to the flesh change.
2) The Corvidae Sgt. survives to escape the planet, and is going to live to try and find out other survivors and the reasons for the Legion's destruction.
3) Sgt Arvida blames Magnus and his arrogance for whatever happened.
4) "Knowledge is Power" he says aloud, which is also Blood Ravens' motto.

1) And? There's any number of feasible explanations of this. Most of the Legion on Prospero weren't afflicted by the flesh change(which is not Ahriman's Rubric, which takes place a bit after the Heresy/during the Heresy depending on how it gets explained due to warp/realtime dilation), only those who really went ape with their powers during the siege succumbed to it.
2) Ehhh. They made it seem more like he was on one of the outbound flights.
3) Which is slightly ridiculous, but acceptable.
4) Again: this is such a commonly stated thing during the course of the Heresy that it's ridiculous to point at it as evidence. The Dark Angels Codex even has had a bit about how knowledge is power.

You can argue individual points. You can choose to disregard Goto's books. But when it's all taken into account, there really is not room for doubt.

When it's all taken into account it's a jumbled mess where people are trying to force pieces to fit their theories. There's too many discrepancies.

And that's even discounting Goto's stuff.

GW is telling us the Blood Ravens are decended from the survivors of the Thousand Sons.

'
Or that the survivors of the Thousand Sons formed the core of the Grey Knights.
Or that they became the foundation of the Deathwatch.
Or any number of potential things.

GW isn't "telling us" anything. They're laying clues down that can point in any direction they so choose.