Kharn: The Eightfold Path is the seventeenth audio drama for the Horus Heresy Series that was not originally released as part of an anthology or other release. Kharn: The Eightfold Path was published online in December 2013 by the Black Library as a part of the 2013 Holiday Advent Calendar, on day number 8. The title was also published as part of the Legacies of Betrayal main series anthology novel.