"Midnight clad, and wielding fear as a weapon, the Night Lords haunt the dark places of the Imperium. They do this not to hide from the light of justice, but because that is where those who would seek to harm the Emperor’s subjects are to be found. Since the time of their Primarch, Konrad Curze, the Night Lords have been guided by visions of the darkest of futures which they are driven to avert, even at the cost of their own lives. By their blood and sacrifice the Imperium of Mankind has been kept safe from rebellions, xenos invasions and betrayals without number."
The Dornian Heresy is the alternative history background being created at Bolter and Chainsword. In a nut-shell, all the roles are reversed (and/or generally perturbed) compared to the Horus Heresy. A couple of weeks ago, the authors published the draft background for the Night Lords, as the good guys.
I must say, I like this take on the Night Lords. They're very focused on keeping the law (through fear) and punish severely those who waver in the eyes of the emperor -- especially those that seek to hide in the dark places. A few of their number also share Night Haunter's precognitive ability -- also a very nice touch. In the revised background, Curze still dies, but this time at the hands of Dorn. He does this to save the Emperor as he sees in his visions the calamity that will befall the Imperium without his sacrifice. His terminal words are recorded as: "Why did I come before you only to be killed? Because your Heresy, and the act you are about to commit, proves the truth of my actions at Cheraut. I merely tried to punish one who would go on to cause so much harm – my only regret is that I did not succeed in killing you before you made war on our father, our Emperor. Death is nothing compared to vindication." which bears a striking similarity (albeit reflected / inverted) to the official cannon.
Gotta like the Loyal Night Lords. They still rock.