"It has been witnessed in the song of the solar fires, and its commutation is found in the fractal patterns of spilled blood and spent shell casing alike, writ as immutably as atomic decay. The program known commonly as "organic life" has almost reached its final solution, its ultimate course is all but run. So declares the Omnissiah plainly and unequivocally for those with the wisdom to understand."
- — Sahalida Khjartan, The Heretek Gnostarch of Antioch Majoris, Proclamations, Vol. CVII/gamma-X
A Herald was a bygone unofficial Consul type rank conferred upon certain Legionaries within both the Loyalist and Traitor factions as well as the Blackshields -- Space Marine outcasts and marauders of uncertain allegiances or origin -- during the Horus Heresy in the 31st Millennium. As the wars of the Horus Heresy spread to consume the galaxy, billions fought and died under the banners of warlords they had never seen or heard firsthand, and even amongst those such as the Legiones Astartes, near-religious fervour became common for those artefacts touched by Primarch, Warmaster or Regent, and given to a chosen emissary as a sign of authority and favour. The Blackshields, having obscured their heraldry or cast aside former masters were no different, their strange sigils or blackened flags becoming totems of destruction and the foresworn. Amongst the Blackshields, these emissaries were known as Dark Heralds.
- The Horus Heresy - Book Six: Retribution by Alan Bligh, pg. 234