The Yasan Sector is a sector of space in the Imperium of Man located in the Ultima Segmentum near to the Warp rift known as the Maelstrom. It is the sector where the White Scars Chapter homeworld of Chogoris is located.
In the midst of the campaigns of the Great Scouring that followed the Heresy, the White Scars returned to their home sector to scour it clean of the remaining Traitors and drive the Drukhari back into the Webway.
The Chapter reclaimed the sector for the Imperium, though during one such battle on the world of Corusil V in 084.M31 the White Scars Primarch Jaghatai Khan disappeared while pursuing Drukhari raiders into a Webway portal.
While a similar invasion befell Chogoris, the White Scars succeeded in throwing back the Red Corsairs offensive, though at a steep cost.
Heretic forces continue to plague Chogoris and the foundation of Chaos outposts in the sector mean the Red Corsairs will continue to present a major threat to the White Scars' home star system for a long time to come.
- Chogoris System - The Chogoris System was liberated from the Red Corsairs' assault, but remnant Heretic forces like mutants and Chaos Cultists remain in place on Chogoris itself, while Heretic raids out of the Maelstrom are a constant thorn in the side of the people of this system's primary world.
- Gartuli System - The Gartuli System dominated by the Fortress World of the same name has almost wholly fallen to the Chaos forces of the Red Corsairs and now serves as a base for their continued operations in the sector.
- Thaxis System - The Thaxis System, once home to the Forge World of the same name, has almost wholly fallen to the Chaos forces of the Red Corsairs and now serves as a base for their continued operations in the sector.
- Codex Adeptus Astartes - Space Marines (8th Edition), pg. 34
- Codex Supplement: White Scars (8th Edition), pp. 8-9