The Thramas Sector is an Imperial Sector on the edge of the Ultima Segmentum. During the Horus Heresy, the Night Lords waged a campaign of genocide across the sector, pursued by the Dark Angels in the Thramas Crusade. The sector was declared perdita by Lion El'Jonson in 009.M31, but conflicts among the remanants of the Night Lords, the renegade Ashen Claws and the Ultramarines 10th Chapter operating out of the Gulgorahd Protectorate continued at least two years later.
- Desperation — destroyed 011.M31, repopulated, destroyed 272.M39
- Tsagualsa — dead world, adopted homeworld of the Night Lords
- 1: Savage Weapons (Short Story)
- 2: The Horus Heresy Book Six - Retribution, pgs. 130–131
- 3: Prince of Crows (Novella), Chapter IV
- 4: Codex: Dark Eldar (5th Edition), pg. 23