The Veritas took part in the space battle above Isstvan V during the Dropsite Massacre. Commanded by Captain Durun Atticus, the Veritas was part of the second wave of Iron Hands vessels to arrive at Isstvan V, having been too damaged in the Emperor's Children ambush on Callinedes to join their Primarch Ferrus Manus in the first wave, and was immediately attacked by the Traitor Legions. In the massacre that followed most of the second wave of Iron Hands vessels were destroyed, with the Veritas taking fire as its crew desperately tried to escape; after receiving word that their Primarch had fallen in battle. As the Veritas made its escape, it suddenly received a vox from two Thunderhawks bearing survivors from Isstvan V's surface and, after being convinced by Sergeant Khi'dem of the Salamanders 139th Company, moved to recover them. While coming under continuous fire the Veritas recovered the survivors, which cost the Iron Hands more lives than the ones they had just saved, before finally making an emergency jump into the Warp, as the traitors' ships closed in on the Strike Cruiser.
The Veritas Ferrum later traveled to Pythos as part of the Shattered Legions expedition there under Captain Durun Atticus. At Pythos, the Veritas Ferrum along with the Legionaries on the damned world were claimed by the Daemon Madail.
Following the capture of the vessel by Madail, the Daemon transformed the Veritas Ferrum into a corrupted monstrosity. The vessel became far larger than it originally was and grew organic features such as jaws, tentacles, and eyes. The damned ship became the center of Madail's fleet as he terrorized worlds across the galaxy. During the Second Battle of Davin the Veritas Ferrum materialized as the head of fleet of Daemonships, laying waste to the loyalist armada and destroying the Ultramarines flagship Samothrace. When Davin was destroyed by Cyclonic Torpedoes the anchor keeping the fleet in the Materium died with it, and the Veritas Ferrum and its escorts vanished back into the warp.