Pertinax was a Captain in the Imperial Fists Legion during the Great Crusade and was a veteran of a hundred battles when the Horus Heresy began. He commanded the Battle Barge Hammer of Terra, when he joined the Retribution Fleet sent, by his Primarch Rogal Dorn, to confront Horus when the Heresy began. However due to severe Warp Storms, the Fleet was left stranded in the Phall System and the Hammer of Terra became the first of the Imperial Fists' ships to face the Iron Warriors Legion, during the Battle of Phall. As the battle began the Contrador, command ship of Captain Erasmus Golg, appeared in the System alone and fired upon the Hammer of Terra; which caused an enraged Pertinax to order the Hammer of Terra's crew to return fire. Before they could do so however, the rest of the Iron Warriors Legion's fleet appeared beside the Contrador and the Hammer of Terra was destroyed, when a hundred of the Traitor's ships fired upon it.