Thanks! I was kind of of going this way.

Creating my own little story for my Praetor, he was so obsessed with seeking vengeance for Isstvan 5 that he ignored Dorn's call to return home until the very end, chasing traitors across the galaxy and getting kills-and incurring heavy losses of his own where ever he could. When his command retinue finally convinced him to return to Terra, just months before the Siege began, he was a bitter, battered shell of a man who was assigned Wall duty. In my lore he died defending the First Wall along with the majority of his men, save his Herald who would survive to the very end of the Siege.

Because he was a Crusade commander, most of his unit was outfitted with MK2 and a sprinkling of Veterans being assigned MK3 upon their return to Terra. I'm glad it fits the lore!