The Thramas Crusade was a campaign conducting by the traitorous Night Lords Legion during the opening years of the galaxy-wide insurrection known as the Horus Heresy in the early 31st Millennium. Following the Traitor victory during the Drop Site Massacre of Istvaan V, the Warmaster Horus Lupercal despatched the homicidal Primarch Konrad Curze and his psychotic VIIIth Legion on a campaign of genocide against the Imperial strongholds of Heroldar and Thramas in the Aegis Sub-sector of the Eastern Fringes located in the Ultima Segmentum, thus protecting Horus' flank and delaying the Dark Angels Legion from reinforcing the Loyalists. This bitterly contested campaign would drag on for nearly three standard years.