The Sons of Antaeus is a Loyalist Space Marines Chapter of the 21st Founding that is a Successor Chapter of the Ultramarines. It is unknown what exactly went wrong, if anything, during the creation of these mysterious Space Marines and what mutant flaws they may possess within their gene-seed.

Like the mythological giant Antaeus, the Astartes of the Sons of Antaeus Chapter are unusually large and robust physical specimens, even among their already superhuman kind, and they are capable of surviving wounds and physical injuries that would kill even other Space Marines.

The Sons of Antaeus' unusual physical abilities may be the result of the mutation in the Chapter's gene-seed that has affected so many other Chapters created by the Imperium during the 21st Founding. There are many rumours as to why they are so difficult to destroy, ranging from reinforced skeletons to enhanced genetics. At this time, the truth remains unknown.

Chapter History

The Cursed Founding

The 21st Founding was the largest Founding of Space Marine Chapters since the Second Founding following the Horus Heresy. It took place in the 36th Millennium shortly before the start of the Age of Apostasy. The focus of the 21st Founding for the Adeptus Mechanicus was perfecting and removing the existing, identified deficiencies in flawed Adeptus Astartes gene-seed, and ultimately the production of new and improved Primarch-like Space Marines as part of what was called "Project Homo Sapiens Novus".

Unfortunately, the Adeptus Mechanicus' Genetors proved far less skilled in the genetic sciences than the Emperor of Mankind, and their efforts resulted in the development of seriously flawed gene-seed that was used to craft the organ implants for the new Chapters. The Founding itself ended when one of its projects, already corrupted by Chaos, sent a signal through the Warp and alerted Fabius Bile, a Traitor Marine who served Chaos Undivided by seeking out new recruits for the Chaos Space Marines, to its existence. Bile had been engaged in his own quest to improve upon the Emperor's work since the Horus Heresy and he found the "improved" Space Marines of the 21st Founding to be creations after his own black heart.

The 21st Founding is also known simply as the "Cursed Founding", because of the appalling bad luck that seems to dog the Chapters that were created by it. Worse still, some of these Chapters have developed unexpected genetic idiosyncrasies, mutations that strain the tolerance of the Inquisition and threaten those Chapters' survival.

As a result, the Chapters of this Founding have gradually dwindled in size as their inability to raise and induct new recruits means that their battle casualties cannot be replaced. The most seriously-afflicted Chapters exhibited spontaneous and extreme physical corruption, turning them into a race no longer human or sane. Most of the Space Marine Chapters founded during this time eventually turned Traitor and swore themselves to Chaos or met a gruesome end at the hands of other Space Marine Chapters and the Inquisition's Ordo Hereticus.

Notable Campaigns

The only official Imperial record that lists the Sons of Antaeus is the Chronicles of the Third Inter-Guild War of the Inca Sector, 850-901.M41. Though it is reported that they have been seen in action by other reputable Imperial forces.

  • Third Inter-Guild War of the Inca Sector (850-901.M41) - The Chapter is listed as having answered the pleas of the Guild Fathers for aid against pirate forces sponsored by business rivals, and according to the records, acquitted themselves courageously before departing. One such eyewitness account, submitted by Captain Rakman of the Subjugators Chapter, recorded an incident in which his force found itself under attack by the Aeldari of the Void Dragons pirate fleet. Surrounded and under heavy fire by the pirates' ultra-rapid anti-gravitic vehicles, Rakman stated that a force bearing the livery of the Sons of Antaeus appeared unexpectedly and attacked the enemy vehicles from behind. Forced to redeploy, the Eldar suddenly found themselves faced with the prospect of having to make a breakout. The Aeldari Falcons and Wave Serpents made straight for the Sons of Antaeus, judging them the lesser of the two Space Marine forces. The incredulous Captain Rakman gave an amazing account of the Sons of Antaeus' stand in the face of a storm of Aeldari firepower, against which the mysterious Space Marines stood seemingly impervious. The Subjugators were able to press their attack on the enemy rear as the Sons of Antaeus held the Aeldari in place, and the xenos pirates were destroyed in short order, caught between the immovable anvil of the Sons, and the irresistible hammer of the Subjugators. As soon as the Aeldari pirates were defeated and the Subjugators were victorious, the Sons of Antaeus vanished as mysteriously as they had arrived.


  • Augmented Skeletons - During the Founding of the Sons of Antaeus Chapter, its Adeptus Mechanicus creators extensively modified their gene-seed in order to create Space Marines of exceptional durability and toughness. Whether or not the Astartes of this Chapter had their skeletons enhanced with some artificial substance, or whether a more esoteric procedure was used is not known. Detractors point out that the Chapter appears every bit as resilient as the heretical Death Guard Traitor Legion, its Heretic Astartes blessed by the Plague God Nurgle.

Chapter Appearance

The Sons of Antaeus Space Marines are apparently larger and hardier than any of the other members of the Adeptus Astartes.

Chapter Colours

The Sons of Antaeus' Power Armour is painted grey and black.

Chapter Badge

The Sons of Antaeus' chapter badge is not listed in current Imperial records.


As with many other Space Marine Chapters, the Sons of Antaeus are inspired by the cultures of certain ancient Terran societies, in this case the ancient Greek mythological figure of Antaeus, an incredibly strong and near-invincible man descended from the god of the sea Poseidon and the Titaness Gaia.

As long as Antaeus' feet touched the ground, his connection to the Earth, his mother's domain, granted him great strength and invincibility. But Antaeus was killed in a wrestling match with the hero Heracles when he realised that by holding the giant in the air, Antaeus became as weak as all other men.


  • Chapter Approved: The Fourth Book of the Astronomican (2004), "The Cursed Founding" by Andy Hoare, Graham McNeill & Phil Kelly, pp. 4-9
  • White Dwarf 279 (UK), "Chapter Approved: The Cursed Founding" by Andy Chambers, Andy Hoare, Graham McNeill & Phil Kelly, pg. 52
  • White Dwarf 260 (UK), "Index Astartes: The Cursed Founding"
  • Deathwatch: Shadowbreaker (Novel) by Steve Parker, Ch. 36
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