Valerius is the forty-first audio drama for The Horus Heresy series that was not originally released as part of an anthology or other release. Valerius was first released as an audio drama in December 2016 as part of the Black Library's 2016 Advent Calendar, on day 16.
Though he knows such beliefs are forbidden, Vice-Caesari Marcus Valerius of the Therion Cohort is willing to lay down his life in service to the immortal God-Emperor, for the good of all Mankind. Sent by Corax to the great slaughter at Beta-Garmon, every last one of the Imperial Army soldiers under his command knows that the end is nigh -- but can Valerius' holy visions guide them to one final victory over the hordes of the hated Archtraitor?
- Valerius (Audio Drama) by Gav Thorpe