Though of limited use against ceramite plating, such artefacts were known to have a devastating effect on those cursed with psychic abilities, particularly amongst certain xenos breeds, and in the later years of the Horus Heresy saw some use among the upper echelons of the forces at war.
The early Imperium was not the first human civilisation contacted by the shattered remnants of the fallen Aeldari Empire. Far older and more debased branches of Mankind had preyed upon the vast Craftworlds of the fleeing Aeldari, plundering their technology.
With their fall, the relics of a number of these ancient human civilisations became trophies of the victorious hosts of the Emperor. Among them were the weapons known as Empyreal Lances, spears crafted from the wraithbone of captured Aeldari spacecraft and defaced with carven glyphs of ancient provenance and dubious purpose.
- The Horus Heresy - Book Eight: Malevolence (Forge World Series) by Neil Wylie and Anuj Malhotra, pp. 300-301