Celtic Sector

The Celtic Sector is a Sector of Imperial space located north of the Galactic Core Region in the Ultima Segmentum. The Celtic Sector is made up of seven Subsectors; Magmell, Erin, Alba, Cymru, Karnow, Vannin, and Breizh. The most important Subsectors are Magmell and Erin. The former being the administrative/military capital of the Sector and the latter being home to the Iron Spears Chapter of Astartes.

The main threat to the Celtic Sector are constant Xenos invasions and the ever-present threat of Chaos incursions. The Celtic Sector is dutifully guarded by the Kern Vanguard, Battlefleet Celtic, and the Iron Spears Space Marine Chapter.

Following the formation of the Cicatrix Maledictum, the Celtic Sector was cut off from the greater Imperium, becoming part of he Dark Imperium. To make matters worse, a warp storm known as the Daedalus Rift formed on the border of the Sector. The Void Stalkers Warband and other forces of Chaos use the Daedalus Rift to launch ceaseless attacks upon the servants of the Emperor. The Sector was partially reconnected with the Imperium through Roboute Guilliman's Indomitus Crusade.

Magmell Subsector

 * Danu System
 * Gallowglass: Hive World that serves as the headquarters of Battlefleet Celtic
 * Dagda: Environmentally stunning civilized world that serves as the Sector Capital. The planetary population is condenced into a single Hive City, leaving the rest of the planet's ecosystem untouched.
 * Kern: Mountainous civilized world that serves as the headquarters of the Sector's Imperial Guard Regiments.

Erin Subsector

 * Brigid System
 * Ailinne: A frozen Feudal/Death World that serves as the homeworld of the Iron Spears Chapter of the Adeptus Astartes
 * Ibrickane: Satellite of Ailinne. A cold and bleak Feral Moon that serves as the secondary recruitment world of the Iron Spears

Alba Subsector

 * Svarog System
 * Svarog III:  Principal Forge World and industrial heart of the Celtic Sector

Cymru Subsector

 * Morrigan System
 * Morrigan: Paradise World with a heavy Ecclesiarchy present. Unofficial "homeworld" of the Sisters of Battle Order of the Wilted Rose and is home to the largest Wilted Rose Monastery. A few milennia ago Morrigan was also classified as a War World

Karnow Subsector

 * Kilandros System
 * Kilandros: Arid Ork World that is the homeworld and "capital" of the Mad Skullz Ork Klan
 * "Da Great Rok": Satellite of Kilandros. In the early 41st Millennium the Mad Skullz attempted to convert the planetoid into a massive "Attack Moon" and crash it into Holy Terra. The Orks' plans were stopped during the Battle of Da Great Rok where the nearly complete "battle station" was permanently immobilized.