|This article is about the the Horus Heresy novel. For other uses of Betrayer, see Betrayer (disambiguation).|
|Series||Horus Heresy Series|
|Preceded by||Angel Exterminatus|
|Followed by||Mark of Calth|
|Length||14 hours 9 minutes|
Betrayer is the 24th novel in the Horus Heresy Series written by Aaron Dembski-Bowden. The hardcover edition was published in December 2012, with the trade paperback scheduled to be published in March 2013. It was later included in "The Novels: Volume 5" eBook collection.
The Shadow Crusade has begun. While the Ultramarines reel from Kor Phaeron's surprise attack on Calth, Lorgar and the rest of the Word Bearers strike deep into the realm of Ultramar. Their unlikely allies, Angron and the World Eaters, continue to ravage each new system they come across - upon the garrison planet of Armatura, this relentless savagery may finally prove to be their undoing. Worlds will burn, Legions will clash and a primarch will fall.