Meduson is a limited-release anthology in the Horus Heresy series. It was published in May 2015 and is exclusive to the Games Workshop Headquarters in Nottingham. It was re-released in an "Ultimate Edition" on 20 May 2016 as both a limited number hardback book with two CDs containing "Grey Talon" and "The Either," e-book, or an Enhanced Audio Edition that incorporated audio elements. The short story "The Hand Elect" by Chris Wraight was added for the re-release.
Driven almost to the brink of self-destruction by the death of Ferrus Manus, the Iron Hands now seek vengeance for the many horrors of Isstvan V. Gathering survivors from the Raven Guard and the Salamanders aboard any vessels capable of warp travel, they wage a new campaign of annihilation against the traitor forces across the galaxy - a campaign masterminded by legendary warleader Shadrak Meduson.
- "Meduson" by Dan Abnett: Shadrak Meduson attempts to restructure the Iron Hands after the Dropsite Massacre and the loss of their primarch.
- "Unforged" by Guy Haley: Examines the broken nature of the Salamanders
- "Immortal Duty" by Nick Kyme: Describes the Battle of Isstvan V
- "Grey Talon" by Chris Wraight
- "The Keys of Hel" by John French: The story picks up from Riven (Short Story)
- "The Noose" by David Annandale: has Iron Hands battle against the Emperor's Children
- "Deeds Endured" by Gav Thorpe
- "Unspoken" by Guy Haley: A continuation of "Unforged"
- "The Either" by Graham McNeill: Tybalt Marr of the Sons of Horus battles against the guerrilla tactics of the Iron Hands.
- The Hand Elect by Chris Wraight.