The Mor Deythan, the Shadow Masters of the Raven Guard, were an elite cabal of warriors who inherited a rare and uncanny gift from their primarch Corvus Corax. Able to bend light and shadow about themselves, they could pass unseen through the fiercest battle, striking from darkness before their prey ever knew death approached.
Drawn from the ranks of the Raven Guard, these shadow-kin embodied the Legion's doctrine of guerrilla war and lightning ambush. Where lesser warriors relied on wargear alone, the Mor Deythan wielded the substance of shadow itself, a legacy woven into their transhuman flesh.
After the massacre at Isstvan V shattered the Legion, the Mor Deythan became rarer still, their numbers bled white in the desperate campaigns of the Shattered Legions. Each surviving Shadow Master was a relic of a fading art, a spectre of vengeance haunting the servants of the Warmaster across the war-torn galaxy.