Gav Thrope
Deliverance Lost
part 18

After their near-destruction at the hands of Horus’ Traitor Legions, the Raven Guard seek to escape and rebuild, but the forces of Chaos are insidious, and the Legion may yet face its doom.
The Horus Heresy
novel

Also in:
Books 16-18: Unabridged Audiobook Collection
The Novels: Volume Four