The Warforged was a Strike Cruiser in the Iron Warriors Legion and served in Warsmith Khrossus's Grand Company during the Horus Heresy. It was among the Iron Warriors' fleet as the Traitor Legions began making their way to invade Terra, but its course was suddenly changed at the Warmaster's behest. Horus had learned that the Primarch Guilliman and the Ultramarines were racing to reach Terra as well, and he ordered the Iron Warriors' Primarch, Perturabo, to send his forces to block the Ultramarines' path. Perturabo needed the bulk of his Legion for the invasion of Terra, though, and only spared Khrossus and his Grand Company for the task, though all knew it was a suicide mission with little chance of success. Despite this, Khrossus did not waver and departed for the Carchera System, which the Ultramarines would need to pass through to reach Terra. Once the Carchera System was under their control, Captain Vûrtaq was given command of the Warforged, as the Grand Company began preparing for their final battle with the Ultramarines.