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"The Battle of Calth"

—Book's tag-line

Know No Fear is the nineteenth volume in the Horus Heresy series of novels.


Know No Fear documents the Word Bearers' surprise assault on Calth, a world belonging to the Ultramarines and the subsequent course of the infamous Battle of Calth. The story starts close to where the timelines of Battle for the Abyss (Book 8) and The First Heretic (Book 14) converge. The invasion is planned and led by the Traitor Primarch Lorgar, now fully and openly committed to the spread of the worship of Chaos. The story starts with the invasion force en route to Calth. The objective is to completely destroy the Ultramarines Legion, the largest of all the Space Marine Legions, and by doing so, cause the creation of Warp Storms due to the destructive energies unleashed by the war. The Warp Storms would isolate and confuse the Ultramarines forces and effectively neutralise them for the remainder of the Horus Heresy. The Word Bearers are also offering this slaughter of Loyalists as a tribute to their new Gods of Chaos. The story tracks the campaign from its opening phases and the actions of several characters. It is a bloody war with dark ritualistic undertones, scorched earth tactics, decisive use of technology, and the considerable involvement of Chaos.