That's now debatable, thou the character is not directly stated to be a Grey Knight there's a story about someone who we are clearly supposed to think is a Grey Knight who assaulted the Palace of Slaanesh itself, made his way to the god, and when Slaanesh appeared to him as a child of flawless purity he lost himself to the Dark Prince. If this is to be interpreted as a Grey Knight falling to Chaos(probably that Dusthead Draigo) then there would no Imperials around to note his fall, and thus it would still be true that no GK ever fell to Chaos. On record at least.
Funnily enough - that was the first Black Library book I read, since then I have read other better and Much Better books - but either way, he is Canon....
Well he is the reason that GW Said that all BL books could be human propaganda. He is as much Cannon as a D-Cannon shooting projectiles. Also the next dawn of war games (witch are also cannon) acted like the cs goto books dident exist
dawn of war book are not even respected by dawn of war game how they can be canon? qlso i don't think that dawn of war is canon not even eternal crusade is canon: we know that eternal crusade can eventually be canon.
This may be old - but I'm sure at one point that GW said all BL material was Canon (unless this has been recanted/retconned)
They probably have a scale of canon: for example the actual Dawn of War novel is how the campaign unfolds, meaning it is as canon as the game, whilst the other two novels in the series are in a lower tier of canon that still has relevance (links between Thousand Sons and Blood Ravens)
Everything is canon, but GW advise people to assume everything is also propaganda. For those familiar with the Fallout quadrilogy, a good analogy is the Overseer of Vault 101 announcing proudly that no-one ever enters the vault, and no-one ever leaves it. Despite knowing perfectly well that people have done both. The game's own introduction presents this statement as undisputed fact. Within 20 minutes, the player will have discovered that's its actually a tissue of lies. The best way to make sense of the Grey Knights is to view it as "The Grey Knights tell the Imperium, and themselves, that no Grey Knight has ever fallen to Chaos". This is canon. The best way to check for propaganda in this case is to ask yourself "...and if any had, would they want that to be known to the Inquisition or to future recruits?" and if you even the smallest shred of cynicism, you'll probably conclude "No, because they're not complete idiots..." So the statement may not necessarily be true. There's just no firm evidence that it's untrue out there in the lore to dispute it. Which doesn't mean that said evidence doesn't exist, didn't exist, hasn't been covered up somewhere in the unwritten lore of the Imperium, etc. It's the same thing that allows the Iron Warriors and Imperial Fists to spin the Battle of the Iron Cage as a victory for their respective sides, even though logic suggests this can't actually be true.
Generally speaking, when you're declared a Traitor by the Imperium at large, you're beyond mortal redemption. The only thing that the Imperium would accept (And grudgingly, if they ever get around to acknowledging this), would be a martyrdom in the name of the Emperor. Said Traitor would need to die, while killing/fighting off/holding the line from some greater threat than he, generally while giving off manly tears and proclaiming his renewed (Or never-ending, if he was falsely accused) faith in the God-Emperor, Master of Mankind. And even then it isn't a guarantee.
