What is the 'Official' fluff now?

Hey, folks. SinSynn here.

One of the most ridiculous arguments I've ever had with the Ultimate Rival, and believe you me there have been many, began due to the inclusion of a Land Speeder in the Horus Heresy novel entitled The First Heretic.
Mind you, this is by far my favorite Horus Heresy book. Aaron Dembski-Bowden wrote it, so that's more or less reason enough for me. More than that, however, I felt that it was the first Horus Heresy book that really focused on the particular Primarch that was it's focus. During the course of the novel, I really got to know Lorgar. I empathized with his desperate need for something to believe in; something bigger than himself.
Unfortunately for him and his Bearers of the Word, the truth you want is never quite exactly the truth you get, and by the time he realizes that it's already too late.
Poor Lorgar.
*sniffle* 
Yup, I loved that book.

When I tried to discuss it with the Ultimate Rival, he scoffed.
'Pffft! That was so bad I couldn't get past the first chapter.'
Surprised, I immediately inquired why.
'The Ultramarines show up right away...in a Land Speeder!'
I'm somewhat confused now. Ok, a Land Speeder. So?
'The Land Speeder wasn't invented until after the Horus Heresy! There were no Land Speeders then! That's why the Traitor Marines don't have them! Duh.'
Ummm....ok, that's some sorta big deal because of why? This is science fiction, after all. It's all sorta made up, isn't it?
'Listen, if the author can't even bother to do a little research and get the fluff right, then I can't be bothered to read it. End of story.'

*And Spock was famous for saying 'never tell me the odds, kid'*

This remains a contentious bone between us to this day. It's hard for us to even discuss Land Speeders in any fashion without one of us inevitably questioning exactly when they were (or weren't) 'invented.'
Cuz, y'know...fictional, flying, sub-orbital hovercraft and their date of inception is critically important to us.
-_-
Yes, clearly we are idiots.

I was able to overlook that particular lil' hiccup in 40k continuity,  but the Ultimate Rival wasn't. I argued that many things have changed, fluff wise, in the years that 40k has been bouncing around. I mean, really, there's a million of 'em; from the Squats to Splinter Rifle wielding Space Marines. Imperial Guardsman on Jetbikes...what about all of that stuff?
'All that stuff was stupid. That's why they got rid of it.'
Sigh- the Ultimate Rival is difficult to debate.

Over the last couple of years, however, the 40k universe has seen some changes. We've gotten some cool stuffs, like Dreadnaught Librarians and the return of Chaos Cultists. We've gotten some silly stuffs, like Blood Angel/Necron fistbumps and (oh gawd I actually bought one...) the Heldrake.
...and then there's the 'so bad it's laughable' category, reserved for the Grey Knights Codex and stuffs written by James Swallow.
...
I suppose it's no coincidence that pretty much all of the 'so bad it's laughable' fluff was written by Matt Ward, right?

*Yeah, that's him*

So what is 'official fluff' nowadays?
As I understood it, back in the day the only fluff considered 'official' was stuffs that came straight from Games Workshop; as in the Rulebooks, Army Books and White Dwarf. The Black Library novels didn't count.
Over time, though, the Games Workshop has increasingly incorporated things from the Black Library into the game of 40k. Similarly, many of the  Black Library books have been based upon events featured in the various game supplements games Workshop has produced. Like, oh I don't know, the Horus Heresy...

Now that we've got 'Allied' armies showing up everywhere, basically spitting in the face of all we've come to know and hold dear, where does that leave us?
Cuz I'll tell ya straight up, I am not cool with the Tau and Space Marines being 'Battle Brothers.'
When the fluff given to us in the 'official' books has jumped the shark, do we turn to the Black Library for answers? Is that the way it works now?

I noticed that many of the lil' one paragraph stories contained in the Chaos Codex have been expanded a bit, and elements from the Horus Hersey books folded into them. I chuckled a bit at that.
I can also admit that I enjoyed seeing one of those lil' stories expanded on in a Novel- Huron and his Alliance with the Night Lords features heavily in Blood Reaver, the second Night Lords novel by (who else?) Aaron Dembski-Bowden.

Last week I read Blood Gorgons, by Henry Zou.

*Recognize the artwork?*

I gotta tell ya, the Blood Gorgons have gotta be the strangest bunch of traitor marines I've ever read about. Not only do they go to bed at a decent hour every night, but they have 'pleasure slaves.'
No, it's never mentioned exactly what they do with the pleasure slaves, but they got 'em. I figure, hey- those cultists gotta be good for sumpthin' other than catching bullets, amiright?
...yes, I am aware that there are no female cultist models, but let's just look past that, ok?

Needless to say, I won't be playing my own Chaos army as Blood Gorgons. And not because of the pleasure slave thing. I just won't hang out with Chaos Troopies that have to be to bed by ten.
Blah.


Until next time- Exit with catchphrase!

-SinSynn