The Grey Raven is the fifty-second short story published in The Horus Heresy series that was not originally part of a main release anthology. The Grey Raven was first published as part of the Black Library's 2016 Advent Calendar, on day number seven.
Balsar Kurthuri of the Raven Guard Legion has always followed his Primarch's orders. When the Edict of Nikaea forbade the usage of psykers within the Legions, he returned to the line squads without a second thought. When the Warmaster Horus' treachery became known, he gave freely of his powers. Now, as the war appears to be entering its final, grim stages, at Lord Corax's command he must return to Terra to face judgement for the apparent crime of unswerving loyalty...
- The Grey Raven (Short Story) by Gav Thorpe