MedHammer 40,000 Ultramar

Founded in Exile, and refounded during the Ultramari Crusade of M33, the Realm of Ultramar has far exceeded the "500 Realms" of Gulliman's founding and at its height covers much of the South West of the Ultima Segmentum. The region is internally fractious and is covered with squabbling noble princes, Mark II clad spiritual warriors, Religiously blessed pilgrims, and Imperial "Advisory Corps"

Imperial Presence

Though the Realm of Ultramar is an "independent ally" of the Imperium by terms of treaty, it is in many ways more closely linked to the Imperium than its rival subject state, the also nominally independent Adeptus Mechanicus. While the Mechanicus is a begrudging servant of the imperium tied by economic and military dependence, the Royum Ultramar is for the most part militarily independent. The Ultramar Realm more closely bound on a cultural, institutional, and religious level than the Mechanicus. The imperium's presence is felt through its joint institutions with Ultramar, particularly the Codex Astartes chapters, who have a outsized presence in the region. Most major systems of Ultramar have some sort of Imperial presence.

Other Imperial Presences

By the 41st Mellenium it was becomming clear to the Imperium that T'au War and Tyrranids were far greater threats than chaos was. As such, Ultramar, being on the forefront of both, has been recieving troops and support from the farthest reaches of the imperium. The Tallarn and Macharian Fleets as well as the Kroot nations have begun to appear with more frequency within ultramar.

Militaries

Ultramar is a heavily decentralized realm, and there are as many militaries as their are planets, nobles, and churches. Though most are negligable, the diversity of Ultramar has led to the rise of some truly exceptional, if not small, forces. These forces are regularlly called by Ultramar to defend against external threats as well as contributions to the Imperial tithes through the Trillieurs.