Aaron Dembski-Bowden
Butcher's Nails

Angron and Lorgar begin a secretive mission together, but World Eaters’ berserk fury soon attracts the attention of xenos raiders who will not allow him to follow this bloody path.
The Horus Heresy
short

Also in:
The Horus Heresy Audio Collection: Volume 1
Legacies of Betrayal
Angron
Word Bearers: Ebundle
The Horus Heresy Audio Drama Bundle 2015