The Carpatia is a stealth-optimised Ultramarines Strike Cruiser and was among the Chapter's forces that took part in the War of Beasts. However Chapter Master Calgar charged several strike forces with seeking out any allies or foes in the Vigilus System and the command of the Carpatia was given to Captain Acheran, as he sought the status of the Industrial World Nemendghast. When they arrived, intercepted signals from Nemendghast's surface told the strike force that the world had fallen to Heresy. However the smog covering the world's atmosphere, prevented them from determining the true extent of its fall and Acheran ordered an immediate deployment to Nemendghast's surface. What they discovered was a hellish world, whose factories that had been remade by the Black Legion to create Daemon Engines and Possessed Chaos Space Marines. Though they were vastly outnumbered, Acheran refused to leave and instead ordered an attack to destroy the Daemon factories. The Carpatia meanwhile, evaded being seen by the Black Legion warships that began patrolling Nemendghast, but this changed when a large fleet of Chaos Warbands appeared near the world. The Chaos fleet soon became alerted to Acheran's attack and as it began moving to aid Nemendghast, the crew of the Carpatia warned Acheran of the fleet. The Captain then immediately led the remnants of his forces in a final attack that destroyed the Daemon factories, but by then they were swarmed by the Black Legion. Acheran knew they could not break free from the Traitors and instead ordered the Vanguard Librarian Maltis, to escape and bring word of what had happened to Chapter Master Calgar. Maltis used his Psychic powers to blind the Black Legion to his presence and successfully returned to the Carpatia, which then escaped to Vigilus where the majority of Calgar's forces were located.