Event · M31

Fall of Yaelis

The Fall of Yaelis was the capture of a hive world of the Thramas Sector, on the Eastern Fringe, during the Thramas Crusade of approximately 007–009.M31, fought between the Night Lords Legion and loyalist defenders. The attack followed a period in which discipline within the Night Lords had frayed while Konrad Curze withdrew into seclusion at Triplex, a lapse that allowed loyalist resistance across Thramas to stiffen, organised through the Thramassi Nightwatch under Regent Mayvin Khelen and encouraged by the defiance of the forge world Gulgorahd. On his return, Curze assembled a counter-offensive drawing on the full strength of his Legion together with the traitor Titans of the Legio Victorum and Legio Phasma. Sheol III fell within a single week, its garrison choosing self-destruction by phosphex rather than surrender, and on Yaelis itself Curze descended in person to break the urban defences of its hive cities. Yaelis did not remain in Night Lords hands. Following the arrival of Lion El’Jonson and the Dark Angels, who first secured Triplex, the primarch turned his forces against Sheol III and Yaelis in turn. The Night Lords met him with delaying actions and slave armies thrown into the fighting to buy time, and the subjugation of both worlds consumed two months before loyalist control was secured. After the loyalists’ victory over the Night Lords at the hive world of Thramas, and with both sides nearing exhaustion, the Night Lords returned to Yaelis and retook it, so that the world was once more in traitor hands when Curze summoned the Lion to Tsagualsa.

See where Fall of Yaelis occurred on the galactic map during the Horus Heresy.

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