By the way, if you really want to enjoy the decadence and corruption of 40K you need to look at older titles. For years now it's being dumbed down, streamlined and made more accessible for "younger" adults and people easily offended. ie. no more amorphous demons with a thousand cocks raping slave-whores in the name of that chaos god that's being slowly phased out.

There are plenty of things that aren't evil in the W40K universe. Surprisingly few races and factions do bad deeds because they like it. They do it because it's their nature or persons gets in the way mostly.

Even time is going backwards it seems, or is there something I haven't understood? Does BC mean something different in the Warhammer universe? Before Chaos, perhaps?

Before Christ. :P
In some text it's even hinted at that The Emperor was JC. ;)

Edit: Yeah I got that wrong. Sorry. My bad. I really need to sleep now.

Sooo... Time is going backwards in the Warhammer universe?
Ah, okay. I'm guessing it should have been AD, then ;-)

No. Ignore BC. It should read After Christ or AD or something logical. My brain is scrambled!

Although, I have only played the Dawn of War series and not the tabletop I have read some of the wiki. It is set in the 41st millenium where humanity is a massive totalitarian theocratic empire dedicated to worshipping the God Emperor who has been on life support for 10,000 years. It has a sprawling military known as the Imperial Guard for the ground forces and Imperial Navy for the space forces and also the Inquisition dedicated to rooting out Heresy, Chaos (Which as it's name suggests, exists to cause chaos.) and Aliens (Which the Imperium also hate by the way.).

10,000 years ago, half of the Imperium's super soldiers known as space marines, led by the Emperor's most trusted General, the Warmaster Horus betrayed mankind for the forces of Chaos led by the 4 main Chaos gods Khorne, Nurgle, Tzeench, and Slaanesh. This is known as the Horus Hersey and The Emperor killed Horus at the end of the Heresy but was seriously wounded and put on life support on a device known as the golden throne. The heresy was also the end of a period of massive expansion by the Emperor and his space marine legions and these legions of tens of thousands were split into chapters of normally no more than 1000 to prevent the heresy from happening again.

By the 41st Milennium, the Imperium has been in a gradual decline since the end of the Horus Heresy. It has gone backwards tecnologically and is pressured by lots of enemies. The Orks are a warlike race who rampage around the galaxy looking for a fight and can be almost unstoppable in a large force known as a WAAAGH!. The Eldar, are a once great race, which are now elusive and follow their own agenda, mostly fighting against Chaos as their fall was because their excesses caused the birth of Slaanesh and Slaanesh now wants their souls. There is also Chaos, which I have already mentioned and many other races are also a threat. Humanity is slowly moving towards collapse and the galaxy is at constant war. It is a great ficitional universe in my opinion, and the OP should definitely check it out.