Battlefleet Calixis

"...and in the last years of Angevin's Crusade, the most holy Saint Drusus did come to the far edges of Imperial space. There, he found his way blocked by vast and terrible storms that raged throughout the Immaterium, and he could go no further. Then Drusus, unwilling to leave what lay beyond in the darkness of heathen unbelief, did order a Watch be set upon the worlds along the Rim. There, his servants would defend the Emperor's worlds from the predications of the dread Halo Stars."

- Excerpt from A History of the Calixis Sector

Battlefleet Calixis is a colossal fleet of Imperial Navy vessels charged with the the protection of the Calixis Sector, an Imperial sector located in the Segmentum Obscurus on the northern edge of the known galaxy, near the Halo Stars and the Eye of Terror. To the trailing edge of the galaxy, the Calixis Sector is bordered by the hazardous territories of the Fydae Great Cloud and to spinward by the Scarus Sector. Battlefleet Calixis origins can be traced back to 384.M39, when the Calyx Expanse was officially declared conquered and the Angevin Crusade at an end by General Drusus. The sector's Naval headquarters is located at the orbital void-station known as Port Wrath within the Golgenna Reach.