Dawn of War 3 is an upcoming real-time strategy game set in the grim darkness of the Warhammer 40,000 universe. Given the rather peculiar art style associated with Warhammer 40,000 the designers at Relic have spent a long time making sure it looks 'right', and whether they have successfully managed to do so you can see for yourself in the latest video.
So if you're interested in a brief overview of Dawn of War 3's environments, level design, and visuals, you'll find the developer-guided preview video right below. Have a look:
On the other hand, if you're more interested in the story and action portions of Dawn of War 3, you will find the "Prophecy of War" trailer over here. It features a brief introduction to each of the factions, as well as a couple of moments of pure Orc-slaughtering gameplay. And don't worry about spoilers, the video is mostly going over the very basics. Enjoy!