|This page contains spoilers for:
|Tallarn: Ironclad (Novel)
Dellasarius was the Governor-Militant of Tallarn when the Iron Warriors Legion invaded during the Horus Heresy and had previously served for most of his life with the Imperial Army during the Great Crusade.
When the Primarch Perturabo ordered for Virus Bombs to be unleashed upon Tallarn, Dellasarius was able to reach one of its underground shelters and from there began to rally the world's survivors to fight the Iron Warriors; as they began to land their forces on its devastated surface. By the time other Loyalist forces from the Imperium began to arrive during the invasion, it was with Dellasarius that they met with, as he had become the leader of what remained of Tallarn's armed forces. Through sheer force of will he united the various factions and military leaders taking part in the battle and began to force them to organize and work together as they fought the Iron Warriors. It was this fact however, that nearly caused the Iron Warriors to be victorious in their invasion, as Dellasarius was later assassinated when his Baneblade was destroyed by one of the Vanquishers commanded by his company of guards; as he journeyed in an armed convoy to another Loyalist base known as the Crescent Shelter. The reason why one of Dellasarius's loyal guards, would kill the Governor-Militant is unknown; but with the presence of the Alpha Legion on Tallarn, it is possible the Traitor Legion may have had a hand in it[1a]. Regardless of the reason, the death of Dellasarius sent discord throughout the Loyalist forces, as they no longer had his powerful presence to unite them, and they began to fight amongst themselves, as to how to continue the war against the Iron Warriors.[1b]