Xi-Nu 73 was a Tech-adept of the 9th Maniple, Carthage Cohort of the Mechanicum's Legio Cybernetica, attached to the 1301st Expeditionary Fleet of the Word Bearers Space Marine Legion during the Great Crusade of the late 30th Millennium. This Imperial fleet was commanded by Seventh Captain Argel Tal of the XVII Legion's Serrated Suns Chapter.