The Cadian 8th is one of the oldest regiments of the Imperial Guard, its low number indicating that it may have been founded in the earliest days of the Imperium, perhaps even dating back to the period before the Imperial Guard and the Imperial Navy became separate branches of the Imperial military following the break-up of the Imperial Army after the Horus Heresy. The Cadian 8th has been destroyed as a functional regiment numerous times following intense combats, but it has always been reformed on Cadia and brought back up to full strength because of its illustrious history of service. The earliest reference to the deeds of the 8th Cadian in existing Imperial records is the Vrakesworld Campaign of the 38th Millennium, though the unit may have been referred to by a different designation earlier in its history.
The 8th Cadian received its highest honour, being named the "The Lord Castellan's Own," during the darkest days of the 13th Black Crusade when their former commanding officer, Colonel Ursarkar E. Creed, was named Cadia's Lord Castellan (Planetary Governor). Creed had served in the 8th Cadian throughout his career and had steadily ascended its ranks over the course of his long career of service. Creed began his service as a young lieutenant in command of a platoon of the 8th Cadian during the Drussite Crusade in 975.M41 and rose to the rank of Lord General when he crushed a raid by the Eldar of Craftworld Ulthwé in 992.M41. When the traitorous Volscani Cataphracts betrayed the Emperor and slaughtered most of Cadia's high command at the Battle of Tyrok Fields on Cadia during the 13th Black Crusade in 999.M41, Creed was appointed to the Fortress World's highest military and political office. The Cadian 8th fought desperately and heroically throughout the 13th Black Crusade, and Creed chose to remain the 8th's commanding officer even as he assumed command of all of the Imperial military forces deployed on the surface of Cadia to throw back the invasion launched by the Forces of Chaos under the command of Abaddon the Despoiler. While Abaddon's forces remain bottled up on Cadia by the Imperial Navy at the present time, the 8th remains at the forefront of trying to purge their world of the taint of the Heretic and the Traitor.
After the end of the 13th Black Crusade, the beloved Ursarkar E. Creed dissapeared, and all records of this deemed classified by the High Lords of Terra. When this happened, the 8th's very own Adrik Federov rose to the rank of Lord General taking the reigns of command of the 8th regiment. From here there seems to be a series of seemingly routine missions turning into calamities with the loss of the entire regiment. Details deemed classified by the High Lords of Terra, but rumors say the sole survivor is Adrik himself. Rumors have circulated the Inquisition has debriefed him themselves and have deemed him fit to raise another command....