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The Serpent Beneath (Novella)

The Serpent Beneath
Author Rob Sanders
Performer Sean Barrett
Publisher Black Library
Series Horus Heresy Series
Pages 101
Collected in The Primarchs

Cover Description

When your entire existence is based around deceit, who can you trust? That's the question that plagues Omegon, one of the twin primarchs of the Alpha Legion, as he prepares a team of elite operatives for the most difficult and dangerous mission any of the Alpha Legion have ever attempted to infiltrate a secret installation controlled by the Alpha Legion itself!


This page contains spoilers for: The Serpent Beneath (Novella)

Omegon, one of the twin primarchs of the Alpha Legion, questions Legion Librarian Ursinus Echion on the status of a high-security Alpha Legion base named Tenebrae Station that is able to manipulate the Warp through a pylon array and that the Alpha Legion have used to keep the White Scars contained and ignorant on Chondax. After ending their conversation Omegon turns to Sheed Ranko, hidden from Echion's sight in the shadows, who helps him form a plan to neutralise a security leak by destroying the base.

Sigma Squad of the Alpha Legion Third Company, led by Sergeant Goran Setebos, are operating on Phemus IV to delay the White Scars conquest of the planet by manipulating Ork movements when they are recruited by Omegon for the mission. Xalmagundi, a rogue psyker with telekinetic powers, flees an attack by the Silent Sisters in an Imperial hive-city and is rescued by Sheed Ranko and Sigma Squad, who recruit her. Omegon tracks down Mechanicum adept and Alpha Legion operative Volkern Auguramus on a trading world and brings him on board. Together, the team plan to infiltrate and destroy Tenebrae base.

Omegon and Sigma Squad infiltrate the Tenebrae asteroid through tunnels in its core and lose one of their members to a gravity effect that crushes him. Carefully bypassing demiurg mining machines that are operating undetected in the asteroid's core and planting explosives they infiltrate the station, killing anyone who notices them. Aided by Auguramus who has taken over the station's security system they split up, Setebos and most of his squad going to neutralise the station's Alpha Legion garrison while Omegon takes two legionnaires to the prison level where captured psykers are used to fuel the pylon array. They free Xalmagundi, who was captured as part of the plan, and Omegon executes Echion for failing to prevent the security leak, but both teams fall into ambushes set up by the garrison's Astartes security officer Arvus Janic. Xalmagundi uses her powers to free the other psykers imprisoned at the facility and create chaos before Omegon sends her to the hangars with a marine to guard her so she can destroy the station's ships, while he goes to kill its Astropathic choir. Setebos's team take casualties and fall back to the hangars. Omegon finds Auguramus's corpse in the security hub after vengeful garrison members broke in, his survival never part of the plan and his last action to sow confusion by telling the station's Mechanicum forces that the Alpha Legion garrison had fallen under the control of the escaped psykers. The explosives the team placed within the asteroid are detonated, aggravating the demiurg mining machines that tunnel up into the facility and cause further chaos. Omegon kills the astropathic choir, preventing them from sending a distress message, but is ambushed by Arvus Janic and takes three bolter rounds to the gut. Revealing his true nature in order to confuse Janic, he escapes when the demiurg machines' attack breaches the station's atmosphere and causes mass decompression. Linking up with the others in the hangar they fall back onto the asteroid's surface, where Xalmagundi is using her power to send the whole asteroid hurtling towards the system's sun. Her job done, Omegon executes her. Squad Sigma ask why Sheed Ranko has not arrived to evacuate them as planned, and Omegon then removes his helmet, revealing that he is Sheed Ranko, sent by Omegon to impersonate him, and that they have all been on a suicide mission since the start. Faced with the hopelessness of the situation, Squad Sigma accept their fate.

On the bridge of the Beta, the real Omegon confers with Alpharius. Their conversation reveals that Alpharius is unaware that Tenebrae station, gifted to the Alpha Legion by the Cabal, has been destroyed, and Omegon lies to imply that the 'security breach' may remain unresolved, having made it up in the first place as a pretext for the station's destruction. Therefore, it can be deduced that Omegon is acting against Alpharius to secretly thwart his actions against the loyalists, destroying the station without his knowledge to rob their Legion of a powerful resource, and is therefore a secret loyalist himself. Retiring to his chamber he views his 'other', seemingly unadorned set of armour, and contemplates his Legion's secretive nature.


Tenebrae station, a top-secret facility capable of manipulating the Warp built into a remote asteroid.


  • Alpharius Omegon - Primarch of the Alpha Legion
  • Sheed Ranko - Captain
  • Ursinus Echion - Librarian, overseer of Tenebrae station
  • Arvus Janic - Captain of security at Tenebrae station
  • Goran Setebos - Sergeant, Sigma Squad
  • Zantine - Legionnaire, Sigma Squad
  • Tarquiss - Legionnaire, Sigma Squad
  • Charmian - Legionnaire, Sigma Squad
  • Volion - Legionnaire, Sigma Squad
  • Vermes - Legionnaire, Sigma Squad
  • Braxus - Legionnaire, Sigma Squad
  • Isidor - Legionnaire, Sigma Squad
  • Krait - Legionnaire, Sigma Squad
  • Arkan - Legionnaire, Sigma Squad
  • Volkern Auguramus - Mechanicum Adept and Alpha Legion operative
  • Xalmagundi - Telekinetic psyker