Macragge is an Imperial Civilised World located in the southern reaches of the Eastern Fringe of the galaxy in the Ultima Segmentum. It is also the Chapter homeworld of the Ultramarines Chapter of Space Marines and the capital of the Ultramarines' Realm of Ultramar. Macragge itself is mostly bleak and rocky, with more than three-quarters of its land mass formed from mountainous upland almost entirely devoid of life. The people of Macragge do not live in this inhospitable region, but the fortress-monastery of the Ultramarines is built here upon a craggy peak surrounded by impenetrable mountains. Within this mighty fortress, inside the vast Temple of Corrections, is the shrine of the Primarch Roboute Guilliman himself. This is where his body sits upon a huge throne of ornately-carved marble.