In the process of creating the Space Marine Legions, the Emperor created twenty clone-sons from his own DNA to serve as templates for the legions. They were scattered across the galaxy by the Chaos Gods in their infancy, to be recovered one by one by the Emperor several years later as the Great Crusade progressed. Roboute Guilliman was found on the rocky world of Macragge by one of the two consuls who ruled its militaristic government. As was custom on his world he was sent to a barracks at the age of six, and within two years had mastered everything his tutors could teach him. While the young Primarch campaigned to pacify the barbarians of Macragge's northlands, the rival consul usurped power and murdered his father, a rebellion Guilliman ruthlessly crushed. As the new Battle-King of Macragge, Guilliman ushered in an era of prosperity, advancement and expansion, so that when the Great Crusade reached the Eastern Fringes, the Emperor found not only a lost son but a model for human civilization.
Given the command of the XIIIth legion, the Ultramarines, Guilliman pushed the Imperium's borders ever outward. Though he was adept in all arenas of warfare, Roboute's greatest talent lay in organization, and each world he conquered suffered minimal damage and quickly became a functioning part of the Imperium. Soon Macragge was the center of a five-hundred-world realm known as Ultramar, which supplied enough recruits to make the Ultramarines the most numerous legion. It is therefore no surprise that when Warmaster Horus turned traitor, he ensured that Guilliman and his forces were isolated far to the galactic south when the renegades marched on Terra.
Guilliman arrived too late to save his father or play any great role in the Horus Heresy, but he was instrumental in holding the Imperium together in the war's aftermath, and his Ultramarines comprised nearly half of the Imperium's manpower in those dark days. This influence allowed Guilliman to implement his Codex Astartes, which broke down the Space Marine Legions into thousand-man chapters so that no one renegade could command such an awesome force. Guilliman met his end battling the Daemon Primarch Fulgrim on the world of Thessalia, and after being fatally poisoned was placed inside a stasis field for transport to Ultramar. His body was put on display on Macragge, and some Ultramarines believe that their Primarch is slowly healing.
Guilliman had a strong belief in rigid order and meritocracy, and had a dim view of people he saw as chaotic and unorthodox. Because of his highborn raising, he was viewed as cold and distant control freak, specially by his own Primarch brothers who he particularly felt to be unworthy such as Lorgar and Agron. In reality, he was humble and respectful towards people that he felt had earned their place, and he did realize that he was an high-achiever making those around feel inadequate. He did the best he could to serve the Imperium's ideals, even if those actions were regarded as self-serving.
Powers & Abilities
He was regarded as one of the most formidable among his brothers, particularly over his statemanship skills and strategy, (having conquered his homeworld and turned into a prosperous near-utopia), an almost peerless grasp of tactics allowing him to excel in every area of warfare, diplomacy and negotiation. His legion, the Ultramarines, are one of the few that came out relatively unscathed during the Horus Heresy, possess a exceptionally low casualty rate and had the highest victory count among his brothers, second to Horus Lupercal.
As a Primarch, he possessed superhuman strength, speed, inteligence, charisma and preternaturally large stature, much bigger than that of a normal human being. He was particularly talented in combat as well, the strength of his blows was so powerful he beheaded Traitor Space Marines by punching their heads off. He faced four Primarchs in combat in separate occasions and was only brought down by one that had already ascended as a Daemon Prince. As with many of his brother Primarchs, Roboute Guilliman possessed a vast selection of weapons and wargear, both to wield on the battlefield as desire and need dictated, and in Guilliman's case also to study and contemplate, so that his arts of war and that of his Legion could be continuously honed and improved.
- Hand of Dominion - His glittering master-crafted blade.
- Gladius Incandor - His power gauntlet.
- The Arbitrator - A heavily costumised Comb-Bolter, one of his favored side arms when in open battle was a heavily customised Combi-Bolter which he was able to wield as deftly as one of is Legionaries might handle a pistol. Dubbed by him the "Arbitrator" for the matters it settled, it was tooled to tolerances beyond any but the archmagos of the Mechanicum to fathom, while its bolt shells were hand-crafted by the finest ordnancer-wrights of the Legion's forges and fitted with micro-atomantic compression warheads.