The Horus Heresy Book One - Betrayal
|Followed by||Book Two - Massacre|
The book deals with the events starting from the end to the Great Crusade until the Battle of Isstvan III. It contains rules and special characters for the pre-Heresy Sons of Horus, World Eaters, Emperor's Children, and Death Guard as well as a Space Marine Crusade Legion army list.
Most of the book is presented as a record written by "A.K." shortly after the Horus Heresy. The first part of the book is a history treatise concerning the Unification Wars, the unification with Mars, the construction of the Astronomican, the founding of the Space Marine Legions and their victories, the Ullanor Crusade, and the seed of treachery that grew within Horus.
The Death of Isstvan III
The Space Marine Legions
This section contains in-depth information on the history of the four Space Marine Legions involved in the Battle of Isstvan III: The Sons of Horus, the World Eaters, the Emperor's Children, and the Death Guard, as well as the Legio Mortis Titan Legion.
The Death of Isstvan III Campaign
This section describes a six-mission campaign for reenacting the Battle of Isstvan III on the tabletop.
Campaign Appendix: Zone Mortalis
This section contains rules for zone mortalis battlegrounds; fighting in confined spaces such as starships and urban environments.
Age of Darkness Battles
This section contains rules for Space Marine Legion army lists set the late Crusade and early Heresy. It describes the force organization chart, allies matrix, units, armour, and wargear available to the Legiones Astartes in general.
Space Marine Crusade Legion Army Appendix
This section contains rules and special characters for the four Legions on Isstvan III.
Mechanicum Army List Appendix
This section contains units for building an Adeptus Mechanicus allied force for a Legiones Astartes army.
- Ezekyle Abaddon
- Garviel Loken
- Shabran Darr
- Saul Tarvitz
- Crysos Morturg
- Durak Rask
- Calleb Decima