Their Primarch, Konrad Curze, called the Night Haunter, knew only one way, that was the use of viscious force. His methods were simple, viscious and direct, if you broke the law you died, there was no appeal, Night Haunter was judge, jury, and executioner upon the world Nostrama, where he had set himself up as a vigilante against the crime lords of the planet. When the Great Crusade finally reached this dark world, and the Emperor was reunited with this dark-visaged young Primarch, Night Haunter was placed in command of the Night Lords. The Night Lords quickly gained a reputation for ruthless efficiency, and a cynical disregard for human life. As long as they achieved their objectives, the means didn't matter to them. When the Emperor recalled Night Haunter to answer the charges of cruelty and destruction against him and his men, Night Haunter quickly defected to the side of Warmaster Horus. Night Haunter, operating from a planet deep in the widerness area of space known as the Eastern Fringe, led the Night Lords on a campaign of terror and genocide that has rarely, if ever, been equalled. Even after Horus had been defeated, the Night Lords continued their attacks until finally the Imperial Assassin M'Shen was able to infiltrate Night Haunter's base and slay the Primarch, with this act the Night Lords quickly stopped being an organised threat to the Imperium. The New Lords now strike from the Eye of Terror, where they have retreated to, and they fight for the pure pleasure of it, and for the material rewards it can bring, and not because they worship some deity. They loo down upon the more dedicated Chaos Marines, and Loyal Marines, considering them fools.
Codex Chaos 2nd ed.
The Night Lords were the 8th Chapter formed during the First Founding. Their Primarch Konrad Curze - later to be known as Night Haunter - grew up on the mining planet known as Nostramo, a world shielded from its sun by a huge moon, and which therefore rests in almost perpetual darkness. The days on Nostramo, such as they are, are only slightly lighter than the pitch-black nights, and the people of the planet grow up with deathly gray pallor. Suicide and depression are facts of life on such a world, and were it not for the huge deposits of adamantium found beneath the planet's surface, it is doubtful that the world would be inhabited at all. Violent crime was also a fact of life on Nostramo, until the young Primarch took it on himself to wage a single-handed vigilante war against the crime lords of the planet, taking on the name of Night Haunter as one that would strike terror into the hearts of his enemies. His methods were simple, vicious and direct: if you broke his law, you died. There was no appeal; Night Haunter was judge, jury and executioner. The Great Crusade finally reached even this dark world, and the Emperor was reunited with his dark-visaged Primarch. Night Haunter was placed in command of the Night Lords, who quickly began to gain a reputation for ruthless efficiency and an almost cynical disregard for human life. Their Primarch's methods became the way of the Night Lords themselves, and as long as they achieved their objectives, the means just didn't matter. Soon stories began to circulate of massacres and atrocities being committed by the Night Lords, some under the supervision of Night Haunter himself, until finally the Emperor was forced to recall Night Haunter to answer the charges against him and his men. But the Horus Heresy erupted before Night Haunter could return, and then it quickly became apparent that all of the charges against him and the Night Lords were true. Night Haunter had no hesitation in joining Horus against the man he started to see as a weak-willed hypocrite, and operating from a planet deep in the wilderness area of space known as the Eastern Fringes he led the Night Lords on a campaign of terror and genocide that has rarely, if ever been equaled. Even after Horus had been defeated the Night Lords continued to attack the Imperium, though increasingly without any discernible plan or motivation for their steadily more murderous attacks. Finally the Imperial Assassin M'Shen was able to infiltrate Night Haunter's base and slay the Primarch, and with this act the Night Lords quickly stopped being an organized threat to the Imperium. The survivors made their way to the Eye of Terror, where they continue to take part in raids on the Imperium. They do not appear to worship any one of the Chaos Gods, and have become instead cynical, hard-bitten and frighteningly ruthless warriors. They fight for the pleasure of it, and for the material rewards it can bring, and not because they worship some deity. This attitude means they look down on their more dedicated brethren, be they fanatical Chaos Space Marines such as Khorne Berzerkers, or zealous loyal Space Marines like the Dark Angels or Ultramarines.
