Dawn of War/WMG

Indrick Boreale was a pawn of Kyras.
Kyras KNEW that Boreale would fail Kaurava campaign, thus weakening the Blood Ravens heavily. Perhaps Boreale's followers were the most loyal of the Blood Raens - those who would certainly not follow Kyras once he will defect to Chaos. Thus, he would remove the opposition in his own chapter so his ascension would be easier.

Boreale, in fact, could be corrupted by Chaos himself, and he might actually be alive, perhaps returning in Dawn of War III.

The Blood Ravens are loyalist Thousand Sons.
It would explain why the Blood Ravens are so interested in knowledge, and want to keep their chapter's secrets hidden so badly. It also explains why they keep calling their Primarch "The Unknown Primarch": they don't want to admit their Primarch turned evil.
 * Or they simply don't know the truth about their origins. The Other Wiki says that the chapter was devastated in a campaign against Chaos where both the Chapter Master and the Master of Sanctity were killed in a trap, so it's possible that the truth died with them.
 * Why was the truth reserved to them? Does any other chapter keep its primarch secret from its own brothers?
 * Well, the Dark Angels keep a lot of things secret about a lot of things - only the Grand Master and whoever he's grooming as his successor know the whole story of the post-Heresy rebellion. Another possibility is that, like the Soul Drinkers, they were excommunicated at one point after making a mistake, but unlike the Drinkers they ambushed the real Blood Ravens, wiped them out, stole their armour and gene-seed, and tried to submerge themselves into deep cover under their new name. It makes sense that they'd want to keep this information from getting out, so they willingly wiped their data...2000 years ago, and only a few hints remain in the traditions (with a bit more being made explicit to higher ranks, like the Dark Angels).
 * A lot of Black Library materal pretty heavily hints that the Ravens are loyalist Thousand Sons.
 * In Dawn of War: Dark Crusade, when the Space Marines assault the Chaos Stronghold, Eliphas (the Chaos commander) suggest that the Blood Ravens are a loyalist faction of the Word Bearers.
 * He suggests the same when he attacks their stronghold.
 * These two theories aren't necessarily mutually exclusive. Another possibility is that the Ravens started out as the loyalists from all the chapters that defected during the Horus Heresy being consolidated into a single one.
 * There is one founding of Space Marine chapters where geneseed from traitor primarchs were used. It didn't work well, and the founding was struck from records. However, it's possible the Blood Ravens are a result of that founding.
 * Go and have a look at Index Astartes: Thousand Sons. Specifically, the pre-heresy TS colour scheme. It's red.
 * Specifically, after Eliphas beats the Ravens, it says that he garnered Abbadon's respect. Why would Abbadon respect him, if not for defeating a first founding legion?
 * Or maybe loyalist Black Legion/Sons Of Horus/Luna Wolves? The existance of such would piss Abbadon off.
 * The Blood Ravens are Fallen Angels!
 * Nah, loyalist Thousand Sons, except that, at the time of Horus Heresy, they were told they could continue if 1) they kept their origin secret and 2) they let their geneseed be modified somewhat by the introduction of some elements from another Legion's geneseed. They therefore kept it secret even from most brothers (so it would never slip out) and chose the Raven Guard as the most compatible, thus explaining why they are not obviously Thousand Sons.
 * A tidbit: The Thousand Sons had, and have, many powerful Psykers/Sorcerers. In some sources, (such as the Lexicanum) the Blood Ravens are explicitly said to have more powerful and more Librarians than most other chapters.
 * The Lexicamum also says they have no record from before M37. Most likely they were made using Geneseeds from the Thousand Sons that were discovered some time after the Heresy.
 * Latest news fresh from the press; the Horus Heresy Novel A Thousand Sons has a scene where a women psyker forsees the Thousand Son's future and explicitly sees a Raven of Blood. Not quite confirmation but a step closer...

Working off of former theory once Magnus finds the Blood Ravens he will betray Tzeentch
This is because Magnus hates Tzeentch because he was his Unwitting Pawn and he lost his legion who he viewed as sons because of the Rubric which was all a plan of Tzeentch. He will one day come to find Gabriel Angelos and defect from Chaos and use his tremendous psychic power to temporarily revive the Emperor being the first person to ever escape Tzeentch's plan.
 * Just as planned.

The Blood Ravens are former Chaos Space Marines that defected back to the Imperium
Which legion they're from is irrelevant. After retreating into the Eye of Terror, the Blood Ravens encountered the Black Library. There, they made some sort of discovery that caused them to abandon the Chaos gods. They managed to reinsert themselves into the Imperium and have since fought loyally for the Emperor. Their origin is hidden because if the Inquisition found out that the Blood Ravens had actually served Chaos, they would destroy the Chapter. Their obsession with knowledge is related to this secret, while their high incidence of psychic powers comes from a generation spent in the Eye of Terror.
 * Add to this the fact that the pre-Heresy Thousand Sons wore red armour... That'd work with the "Still-loyal even though the rest of the Legion turned" theory, but a bit harder toe scape, and goes right with the psychic powers and secretive nature.
 * They went back to red armour, just as the betrayed Sons of Horus went back to the name "Luna Wolves." A symbolic recanting. (Which does not settle the question of whether they could escape afterward.)

By Retribution, the Dawn of War canon is no longer in the 41st millennium.

 * Kinda' nitpicky, but fairly provable. The Tyranids shown throughout the installments (barring those on the Judgment of Carrion, which to be fair should be populated by nothing but Genestealers) have the color scheme of Hive Fleet Leviathan. These guys show up in the galaxy at around 997.M41 (40,997 AD in our notation). Giving the writers the benefit of the doubt, let's say the Tyranid attack on Subsector Aurelia happened in 997.M41. Chaos Rising is one year later, putting it at 998.M41. And Retribution is a full decade after this, so at the most conservative estimates, the year is now 008.M42 (or 41,008 AD), i.e. the 42nd millennium.
 * That works for me. What with Games Workshop's refusal to move the story forward, it is nice to see that someone actually is pushing things along. Also, the first game most likely does take place in 997.M41, since the Tyranids are still somewhat unknown to the Imperium apart from Cyrus and the Death Watch. But how do you explain the Hive Fleet Behemoth Nids that show up in Retribution?
 * Maybe they popped up on the Judgement of Carrion in the intervening years, or another splinter hive fleet attacked the subsector?
 * Not the first time its happened, Ciaphas Cain is written and edited during the 42nd millennium not only that but the sixth book is entirely from the perspective of the 42nd century versions of the characters. Not much has changed though.

The Blood Ravens were never traitors at all. There's just something wrong with their geneseed.

 * The reason they guard this so secretively, to the point of destroying and even in some cases forgetting their own history, is because their geneseed gives them a predisposition to psychic powers, hence their large numbers of Librarians, and the only known chapter to unite the offices of Chapter Master and Chief Librarian. This also makes them much more susceptible to chaotic taint than any other chapter, so much that an Inquisitor would look at them and see Chaos Marines waiting to happen. Not wanting to be exterminated, they scrapped and ferociously guarded their own records. Lo and behold, a number of Blood Ravens fell to the temptations of Chaos in Chaos Rising and Retribution.
 * Taldeer figured it out in her Ham-to-Ham Combat with Thule in Dark Crusade, hence the epic burn Thule got, and why Taldeer was merely "captured" in their ending. She had figured out their psychic predisposition, probably even predicting the fall of some of the Blood Ravens to Chaos. Taldeer basically told Thule that she knew his chapter's dirty little secret, and Thule didn't want that secret going very far, and so he had her captured. The "secrets of Kronus" that Thule was so concerned about was in fact the big secret.
 * For all we know, the Blood Ravens geneseed  which would, at the very least, be extremely humiliating for the Blood Ravens as a whole! Not to mention grounds for inquisition, at the worst.
 * Eliphas could probably sense it, too. The reason he kept calling the Blood Ravens "brothers" wasn't because the Blood Ravens used to be traitors, but that they would be traitors in the future. And at least one of them would be:.
 * Indrick Boreale probably figured this much at Kaurava. While a pretty sucky tactician for not being able to actually win the war at Kaurava, he realized that he couldn't let the Sisters of Battle figure out about this little quirk in their geneseed. And so, when things started looking bad, he deliberately led an entire five companies to their deaths, rather than letting the canonically-victorious Sisters of Battle figure out their little quirk.
 * ... And your source for the Bolter Bitches' victory? Personally, I think Firaveous 'METAL BAWXES' Carron won. The pre release information for Chaos Rising a year ago said eh had 'dealt terrible wounds to the Blood Ravens in Kaurava'.
 * The most popular theory is Vance "Motherfucking" Stubbs was the victor of the Kaurava campaign, but I personally think it was the Tau they had done the least absolutely stupid things of the armies.

Sindri was the only Alpha Legion member on Tartarus.
This is a big inconsistency, as a Legion with few soldiers and whom take great care to remain undetected apparently possess a large combat force and exhibit far from subtle behaviour. The is because Bale and his hoard were Chaos Marines from another Legion (possibly the Night Lords, considering Bale's concern for avoiding open confrontation would be consistent with their strategies) that Sindri merely hired/coerced into working for him, painting them with his Legion's colours and iconography for intimidation and misdirection purposes. Sindri, being Sindri, knew that those under his command would suffer total losses and instead of sacrificing his own brothers he endeavoured to use expendable patsies.
 * This is now officially what happened. +1 Internets to you, sir. In the same vein then, the Chaos Marines in Soulstorm were actually another legion (most likely a World Eaters splinter faction given Carron's melee fixation, Khornate altars and sheer frothing-at-the-mouth senility) who were given Alpha Legion uniforms as part of a misdirection effort. Why? If we knew that, they wouldn't be the Alpha Legion...

Sindri's goal was to prepare the Blood Ravens for the Black Legion's machinations.
This is another inconsistency, as a member of a Legion whose loyalty to Chaos is indistinct was adamant in releasing a powerful Daemon. This is because the Daemon was not the ultimate goal - he knew that Angelos would defeat him and banish the Daemon, if belatedly - but Angelos himself. Not only did his victory swell his acclaim within the Chapter, inspiring many of its other heroes such as Thule, but the events on Tartarus, so soon after Cyrene, hardened him to an almost incorruptible level against Chaos. Indeed it was Angelos and the people he inspired that not only prevented Aurelia from being eaten, but were able to resist the corruption from without and within and stop both Eliphas and Ulkair, and with Retribution it seems as if his inspiration will lead to the final purge of Chaos from the Chapter that began with Kyras a thousand years ago. Just as planned.

As for Sindri, becoming a Daemon Prince was an unavoidable side effect of releasing that much Warp energy at once, either that or be destroyed entirely, and he hasn't appeared again because he was subsequently stuck in the Warp and can't help his brothers directly, though he is probably taking great joy in disrupting the Legions that take refuge in Warp Rifts.

Tau Harbinger drones are based on Necron tech
Based on a "Tau are/are descended from Necron'tyr" theory I've seen. The drones are constructed from seemingly nothing, requiring only a small amount of energy to launch and disappear from the battle field on dying. BUT! Being based on Necron tech, possibly the same living metal, which teleports the Necrons away if it takes too much damage, the drone's remains are actually teleported back into the Harbinger for repairs, and then launched again. This also explains why there are only a limited amount of drones at any time: because there is onlya small amount of living metal available.

Further arguments for the the Tau~=Necron theory include the fact that Bodyguards can be summoned to specific points (in this case, the Ethereal) like Warriors and Flayed Ones, and the fact that the Dark Crusade Necron stronghold shows that their buildings explode with a blue-white Sphere of Destruction, which is seen in Tau orbital strikes.

The Ork Warboss in Soulstorm wasn't Gorgutz
It was another, lesser warboss who assumed Gorgutz's identity to impress the locals, who'd heard all about Gorgutz's feats on Lorn V and Kronus. This is why his voice was so different, and why he was behaving so out of character ie. totally passive (actually letting them show him around? And explaining what the plan is? I don't think so. Not the Gorgutz we know). The real Gorgutz is still drifting around space on a Rok somewhere, having never made it to the Kaurava system.

Neroth is Sindri
I don't even think I need to type this. It's just so obvious. If Eliphas can return from the dead, then Sindri can too.
 * I doubt it, as Neroth is hardly subtle, seeing as he keeps wanting to burn everything that gets in his way.

Unless explicitly stated otherwise, each of the games with Multiple Endings have a mixture of the endings as their "true" ending.
Winter Assault has Taldeer use the Soul Stone to blast the first wave of Necrons, but after she realises it's insufficient she allows Sturnn to awaken the Titan to use its weapons against them, afterwards leaving the planet, Sturnn clearing it of Orks and Chaos and reclaiming the Titan. Meanwhile, Gorgutz kills Crull and claims his skull, before leaving himself.

Dark Crusade is all the Blood Ravens ending however, as conversations in Dawn of War II, Chaos Rising and Retribution have them defeat the Necrons, Guard, Chaos and Eldar, and some wargear descriptions have them defeating the Tau (that still leaves Orks, but it's probably a given that Gorgutz managed to escape again).

Chaos Rising has Angelos declare the Commander to be Captain of the fourth company, but in order to fool Kyras has him and Thaddeus on a campaign somewhere far away from the sub-sector, calling him back to the main force of the Chapter after he himself is declared Chapter Master.

Retribution has Diomedes defeat Kyras and Angelos declared Chapter Master, Adrastia clearing the sub-sector of heresy and halting the Exterminatus, Bluddflag commandeering the Judgement of Carrion as his new Kroozer, Eliphas escaping to plague the Blood Ravens for years to come, Ronahn reclaiming Taldeer's soulstone, and the Hive Lord rejoining the Hive Mind to share the knowledge it has obtained of the sub-sector.

I'd mention Soulstorm, but that doesn't exist.

Dawn of War 3 will give Chaos more Tzeentchian units, including a Lord of Change as their Super Heavy unit.
Dawn 1's Chaos units had a Bloodthirster as its "big" unit, while Dawn 2 had a Great Unclean One (which seemed to be Ulkair again in Retribution, at least in the Chaos campaign). Slaanesh, apart from a Keeper of Secrets being blatant Adults Only bait, doesn't seem to lend itself well to a war setting.

Indrick Boreale will return in Dawn of War 3.
Possibly as a Chaos Champion of Malice?

Kyras knew that Kaurava would be a total wipe.
What better way to throw the chapter into disarray than to have its numbers roughly halved? As a bonus, this also made the chapter's recruiting worlds more crucial to protect, thus making the chapter more likely to fight any threat that descended upon it, unwittingly providing more blood for the blood god. As to why he tried to stop the Blood Ravens from directly engaging the Black Legion? Two possibilities: he felt that a direct skirmish would end the conflict too quickly, foiling his plans, or he knew that the likes of Angelos would not simply follow the safest course of action (after all, that is how he came to the decision to smash the daemonstone in the first place).

Scott McNeil is Alpharius.
Every significant Alpha Legionary has been voiced by McNeil--masquerading as a voice actor would be the kind of subterfuge they're known for. And with his propensity for talking to himself in some series (see Beast Wars or the Mega Man cartoon), compared with the fact that every member of the Legion claims to be Alpharius...

The Blood Ravens are based on the Brotherhood of Steel from Fallout.
They both have the same obsession with capturing and guarding knowledge.
 * It would probably be more accurate to say the brotherhood is based on the Mechinicus
 * That said, the Brotherhood is one of the closest imitations of the Space Marines to be found in other settings. Given their general aesthetic and their monastic, hyper-religious Catholic Knight attitude.

Abbadon the Despoiler will return with cybernetic arms.
This will probably be done as a reference to a certain insistence by the fans.

The Alpha Legion wanted to replace Abaddon with Kyras.
In Retribution, it is revealed that Abaddon The Despoiler views Azariah Kyras as a threat, hence sending Eliphas to deal with him. However, the Alpha Legion has been working alongside the Maledictum Daemon for decades. They planned to use Kyras to overthrow Abaddon and finally defeat the Imperium, thus fulfilling the prophecy that the Cabal showed Alpharius, and destroying the Chaos Gods in the process. However, the plan has a backup as well. Should Kyras be defeated, then Eliphas ascends to Daemonhood. Knowing Eliphas' treacherous streak, the Alpha Legion would expect him to betray his master Abaddon much like he did Araghast, thereby installing a far more capable leader for the Black Legion. A leader who would be competent enough to launch a successful Black Crusade.

The Sergeant from the first cinematic cutscene is Indrick Boreale.
Notice his rather loose grasp of tactics when occupying a more or less fortified position. He got better time for Soulstorm.


 * /tg/ agrees with you.