The 63rd Expeditionary Fleet was one of the Imperium of Man's interstellar military expeditions sent out as part of the Emperor of Mankind's Great Crusade to reunite all the human-settled worlds of the Milky Way Galaxy under his rule during the 31st Millennium. The 63rd Expedition was commanded by the Primarch and Warmaster Horus of the Luna Wolves (later renamed the Sons of Horus) Space Marine Legion. It formed the core of the Traitor forces that would challenge the Emperor for control of the Imperium during the terrible interstellar civil war known as the Horus Heresy. The 63rd Expeditionary Fleet's attached Imperial Army contingent included the Byzant Janizars, commanded by Lord Commander Hektor Varvarus. The 63rd Expedition also had the powerful Legio Mortis Titan Legion attached to it as well as Horus' massive flagship, the Battle Barge Vengeful Spirit.
- Horus Rising (Novel) by Dan Abnett
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- False Gods (Novel) by Graham McNeill
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