The Blood Pact is a highly organized Chaos warrior-cult devoted to Khorne.
Unlike many Chaos cultist warbands, the Pact fights as a disciplined army, and this is what makes them so effective compared to the disorganized Chaotic masses. Consisting of highly trained, vicious soldiers and alien mercenaries, the soldiers of the Blood Pact know no fear or hesitation. They have overrun entire worlds and caused the people of the Imperium no small amount of suffering and woe.

Unlike most Khorne worshipers, the Blood Pact favors a more disciplined and tactical style, utilizing martial aspects of the War God besides that of the berserker. This means that the average Blood Pact trooper will be armed with a lasgun or autogun as his primary weapon. In close-quarter environments such as trenches or when storming techniques are required, they favor plate or chain mail tunics and arm themselves with billhooks, trench clubs and grenades. Some are able combat specialists in the field of demolition or sniping.
Blood Pact units will often contain a mix of heavy and support weapons akin to those of the Imperial Guard. Some Imperial tacticians claim that the officers of the Blood Pact deliberately style themselves on the Imperial Guard, and it is certainly the case that traitor Guardsmen are used to hone and improve the basic combat abilities of the Pact. Such traitors, due to their relative rareness, are distributed throughout the Pact's numbers to disseminate good techniques. Others point out that Blood Pact armaments resemble those of the Imperial Guard because these are the most commonly plundered. Several munition-producing Forge Worlds - especially Neffethyl and Urdesh - were amongst the planets conquered in the Sabbat cluster, and from them the Blood Pact have enjoyed a ready supply of Guard-quality weapons.
The Blood Pact - thanks to these captured Forge Worlds - have numerous armor and artillery formations. Blood Pact armor is generally slightly inferior to standard Imperial, most of it being Urdeshi-pattern variants such as the STeG 4, and the AT70 Reaver-pattern tanks, though they do also have more limited numbers of the larger and more powerful AT83 Brigand-pattern tanks, as well as a few of the rare Baneblade super-heavy tanks. The Blood Pact also field a lighter-armored variation of the Defiler known as the Stalk tank. All Blood Pact armored vehicles are painted red, inscribed with numerous obscene Khornate slogans, and are often decorated with the skulls and hides of their enemies.
In addition to their fearsome weaponry and vehicles, the Blood Pact have special psykers known as Gore Mages. These dark wizards can possess Blood Pact warriors with Daemonic spirits, turning them into ferocious, almost unstoppable creatures that they call Blood Wolves. Also, Gore Mages radiate a sense of irrational fear and have access to many other powers involving blood.