Immortal Duty is the sixty-first short story published in the The Horus Heresy series that was not originally part of an anthology novel. Immortal Duty was first published in the limited-edition Meduson anthology novel, but was later republished in the Shattered Legions anthology book.
Ahrem Gallikus, Medusan Immortal and disgraced warrior of the Iron Hands, faces death -- at the hands of his own brothers. But first they would know his story -- the story of his greatest battle, against his erstwhile allies on board the warship Retiarius in orbit of the world where their Legion was shattered -- Istvaan V. Forming part of a boarding action, Gallikus took the battle to the Traitors -- but what happened, and why has it led him to where he is now?
- Immortal Duty (Short Story) by Nick Kyme