The term "Blackshield" came to be used during the period of the Horus Heresy known as the Age of Darkness in the early 31st Millennium to cover a wide range of Space Marine outcasts, marauders and those Legiones Astartes of uncertain allegiances or origin. Mystery and suspicion attached themselves to such warriors regardless of their true loyalties or intentions, and while some did deliberately scour their old heraldry from their armour or replace it with some false device or heraldry of their own, their name of Blackshield was often a literal description for armour over-masked or simply scorched black.