The Helican Sub-sector is a sub-sector of the Scarus Sector, which is situated in the Segmentum Obscurus. Jeromya Faurlitz IV is currently the sub-sector's Imperial Governor and Lord Commander of the Astra Militarum forces in Helican. He has established strong political ties to the Imperial Warmaster Honorius present in the sector. The Helican Sub-sector was the site of the Helican Schism, a wave of rebellion, terrorism and sabotage that swept the area in the early 41st Millennium.
- Thracian Primaris (Hive World) - Planetary capital of the Helican Sub-Sector, Thracian Primaris glows like an oozing, cataracted eye. The planet has no moons and its populace lives primarily in hive cities scattered across seven-tenths of the surface. Guarded by five Ramilies-class Starforts and with a Planetary Defence Force of 8 million men, the planet is as well-defended as any Imperial world.
- Anemae Gulfward
- Bonaventure - A world where ancient wheel-like tombs were discovered, a possible remnant of the pre-Imperial xenos civilisation known as the Saruthi. This world was the birthplace of the Untouchables Alizebeth Bequin and the Imperial agent and scholar Kara Swole, both of whom served the infamous Inquisitor Gregor Eisenhorn.
- Bradell's World
- Cobalt II
- Damask - A world that was colonised in 700.M40, and lies on the outer edge of the Helican Sub-sector.
- Gudrun (Civilised World) - Former sub-sector capital planet which has had a human presence for over 3,500 standard years.
- Hesperus - A notable world that produced agricultural goods such as wine and corn. It is located on a trade route through the Helican Sub-sector.
- Hubris (Ice World) - A world named for the enormous pride of the original human colonists who founded a successful society despite the harsh and extreme climates.
- Messina (Civilised World)
- Respa III
- Thessalon) (Feudal World) - A small feudal world located in the Helican Sub-sector that lies close to the world of Hesperus. In 343.M41, this was the site of an Inquisitorial conclave held between notable Inquisitors Gregor Eisenhorn, Commodus Voke, an emissary of Inquisitor-General Neve, Massimo Ricci (envoy of Inquisitor-Lord Rorken) and Titus Endor.