Calas Typhon hailed from the Death Guard's eventual homeworld of Barbarus, and possessed the blood of the warlords that had ruled the planet before being defeated by Mortarion, the Death Guard Primarch. He also possessed formidable psychic powers...and had already sold his soul to the Dark Gods of Chaos. With their aid, Typhon became the First Captain of the Death Guard and commander of the battleship Terminus Est. When Mortarion joined Horus in the worship of Chaos, Typhon killed the Navigators who remained loyal to the Emperor and assured his Primarch that he could lead them to Terra. Instead, he led them into a trap - becalming the Death Guard fleet in the warp, adrift, helpless...and at the mercy of Chaos.