Born to freeholder parents in one of many of old Albia's soot-blackened castram-hives, the Astartes that would later take the name Lugos Sul was made note of early by Xth Legion drillmasters for his charisma and leadership potential. Subsequently blooded by the Stormwalkers' campaigns against Lyasx and Orkoid xenos-broods, it was the first Imperial foray into the galactic core that would begin to forge his legend. Sul, then a Line-Captain and going by a name lost to history, would prove himself an exemplar of the hardiness expected of his Legion, commanding his fellows and attached Imperial Army forces against the equally resilient Kinfolk. Fierce tunnel-fights and grinding boarding actions against a dug-in, determined foe characterized this set of brutal campaigns, commonly called the 'Core Wars' at the time. Ultimately, however, the war proved inconclusive for the burgeoning Imperium, with little territorial gains to show for its casualties.

After the discovery of Ferrus Manus, he took part in campaigns against the Eldar, Diasporex, and the Astranii, taking well to the Iron Hands' renewed creed of precise, measured destruction. While accepting minor cybernetic augmentation, the newly rechristened Sul never quite took to the creeds of Mars the same way his fellows did. While this slowed his advancement in the Legion hierarchy, it did not stop it, and by the time of the Heresy, Sul was a fully-fledged member of the Praetorate.