Burden of Duty is the seventh audio drama for the Horus Heresy Series that was not originally released as part of an anthology or other release. Burden of Duty was released as an MP3 format download in October 2012 and was written by James Swallow. It was later re-released as an audio CD alongside the story Grey Angel, but can still be bought as a stand-alone audio drama MP3. The story was also published as part of the Garro main series anthology novel.
As the Renegade forces of the Warmaster Horus storm across the galaxy, a very different kind of war rages in the shadows of the Imperium -- the Knights-Errant, chosen of Malcador the Sigillite himself, move quietly in the dark places where others cannot. Battle-Captain Nathaniel Garro makes his way to the Imperial Fists' mighty starfort Phalanx, seeking out another kindred soul for his elite band of warriors.
- Flight of the Eisenstein
- Garro: Oath of Moment
- Garro: Legion of One
- Burden of Duty
- Garro: Sword of Truth
- Garro: Shield of Lies
- Garro: Ashes of Fealty
- Garro: Vow of Faith
Nathaniel Garro and his Knights-Errant also make an appearance in the novel Vengeful Spirit. All of these stories, with the exception of Flight of the Eisenstein were later included within the main series anthology novel Garro.
- Burden of Duty (Audio Drama) by James Swallow
- Garro (Anthology) by James Swallow