Ultramar - Government: Ultramar is unique amongst the demesnes of the Space Marines. Where other Chapters rule over a single planet, asteroid or, in some cases, a mobile Chapter fleet or orbital fortress, the Ultramarines have a far larger feudal demesne. Before the Horus Heresy, the Realm of Ultramar consisted of more than five hundred worlds, and was commonly referred to as the "Five Hundred Worlds of Ultramar" or the somewhat heretical "New Empire." These 500 worlds were all themselves divided into fiefdoms. The largest was the Ultramarines' homeworld of Macragge, with the fiefdoms of the worlds of Saramanth, Konor, Occluda, and Iax all varying in size. Before the Word Bearers' surprise assault on the world of Calth during the Heresy, there was talk of Calth gaining its own fiefdom due to its industrial output nearly rivalling that of Macragge before the Traitors destroyed its biosphere during the Battle of Calth.The fiefdoms of Ultramar were ruled by officials called Tetrarchs, similar in function and precedence to later Imperial Sector Governors, each an Ultramarines Captain or Chapter Master chosen for this position by Roboute Guilliman, the primarch of the Ultramarines Legion. The Tetrarch would then choose both a military governor, an Emperor's Champion and his honour guard for his region of the realm.After the Horus Heresy, during the Imperial reforms overseen by Guilliman during his first tenure as the lord commander of the Imperium, when the Space Marine Legions were broken down into smaller 1,000-man Chapters, the Five Hundred Worlds of Ultramar were divided up and given over to the many Successor Chapters of the Ultramarines or simply allowed to become autonomous, as Guilliman found himself uneasy in the wake of the Heresy with the idea that Space Marines should rule over mortals as a type of governing warrior caste.The Ultramarines Chapter kept control of the original political and economic centre of Ultramar, consisting of no fewer than 11 local star systems, each with its own worlds and governments loyal to the Chapter. All the worlds that once comprised the larger Realm of Ultramar in the region still share a common cultural heritage with Macragge, so it is not surprising that their styles of architecture, government, and societal traditions are similar.For ten thousand standard years, this was the political structure of Ultramar. Then, in ca. 012.M42, after his return to Maccrage following the end of the first phase of the Indomitus Crusade at the Battle of Raukos and his intervention in the Plague Wars, Guilliman announced that he had made a grave mistake when he had allowed the official borders of Ultramar to shrink so drastically in the days after the Horus Heresy.Instead, he reestablished the ancient ruling Tetrarch Council for Ultramar, and tasked its newly-appointed Tetrarchs, including his Primaris Space Marine Equerry Captain Decimus Felix and the Ultramarine First Captain Severus Agemman, with beginning to expand the territories of Ultramar to include all of the star systems that had once contained the Five Hundred Worlds. This is a mission which has become even more crucial in the wake of the Plague Wars, as Ultramar now faces a continuing threat from the nearby Scourge Stars.At the time of the Plague Wars, Ultramar had expanded to approximately three-quarters of its pre-Heresy size. Guilliman was informed during the Battle of Raukos by Captain Uriel Ventris that the planetary governors of the remaining former member worlds of the realm had refused to recognise Guilliman's authority, claiming that they could find no proof of the ancient treaties that had bound their worlds to Ultramar or even outright claiming that no such relationship had ever existed. Guilliman explained that such behaviour was the way of Humanity, but that ultimately, the governors of those worlds would either submit to his authority and rejoin Ultramar or be executed.