Kristos was an Iron Father of the Iron Hands. A commander of fame in the Chapter's history, he took command of Clan Raukaan after the Skarvus Ambush and led the Clan-Company to victory in the Slaughter on Dawnbreak and Battle for Columnus. The Columnus victory over Orks victory proved controversial, as during the battle Kristos deliberately sacrificed Raven Guard allies. Kristos insisted that it had allowed him to score a victory and was the most logical course of action, but others on the Iron Council suspected he had been personally motivated to betray his allies. In the ensuing two-century investigation of Kristos' conduct known as the Kristosian Conclave, the Iron Hands became divided as the affair evolved into a discussion of the Chapter's entire philosophy. Kristos formed a bloc of allies within the Iron Hands, which became known as Kristosians.
After word of sightings that the Sapphire King and his Emperor's Children warband were active in the Gaudinia System, a now-ancient Kristos swiftly led Clan Raukaan to attack, ignoring pleas by other Iron Hands commanders for caution. When Kristos landed on Gaudinia Prime, he encountered a vast factory-complex where billions of Imperial citizens had become fused with machines by the forces of Chaos. Coming to think that this hideous monstrosity was the ultimate act of perfection and machine efficiency, Kristos became corrupted by Slaanesh and fused with the flesh-machine mass. The Kristosians soon followed, and the Gaudinian Heresy erupted from within the ranks of the Iron Hands. Kristos himself was transformed into a hideous bulging mass of flesh and metal, and was killed following the death of the Sapphire King.