The Cardinals Crimson are an ancient and warlike order of the Adeptus Ministorum, the state church of the Imperium of Man. A mysterious and highly secretive religious order of warrior-priests who view themselves as analogues of the many ancient faith-based knightly orders of Mankind's past, they are known for their unflagging devotion to the God-Emperor and a high degree of fanaticism in seeking to carry out His will. Because of this combination of zeal and combat skill, members of the Cardinals Crimson often serve as bodyguards and honour guards for high-ranking priests of the Ecclesiarchy who use such forces to assist them in the execution of their duties (and Heretics).
Known as Battle Conclaves, these groups are necessarily small; anything larger would breach the prohibition of "men under arms" as laid down in the Decree Passive that prohibited the Ecclesiarchy from raising its own military forces in the wake of the abuses carried out during the Age of Apostasy in the 36th Millennium by the Renegade High Lord of Terra and Ecclesiarch Goge Vandire. Even so, the Inquisition's Ordo Hereticus covertly monitors the activities of the Ecclesiarchy's Battle Conclaves to safeguard the spirit of the Decree Passive, if not its letter. Many members of the Cardinals Crimson who join the Battle Conclaves choose to become Crusaders, potent close combat specialists who often serve the Ministorum and the lords of the Inquisition.
- Dark Heresy: Ascension (RPG), pp. 50-51
- White Dwarf 380 (UK), "Sisters of Battle, Ecclesiarchy Battle Conclaves", pg. 96