A Thallax armed with a Photon Thruster.

A Photon Thruster Weapon is a class of directed energy weapons employed by the Myrmidon Destructors and the Thallax cohorts of the ancient Mechanicum. The secrets of their construction and operation were closely guarded by the Tech-priests of Mars.

When fired, a Photon Thruster Weapon unleashes a howling, needle-thin beam of pure blackness that is able to pierce the densest forms of matter and destroy the most heavily armoured warriors and vehicles. The power source for these weapons are considered extremely unstable and are little understood even by their operators.

At times, the weapon's power source can fail catastrophically, resulting in the wielder being consumed by raging black flames.

Photon Gauntlet

The Photon Gauntlet is the smallest and shortest-ranged variant of the Photon Thruster Weapon. Its mechanism is embedded within a gauntlet that can be fired by the wielder.

Photon Thruster

The Photon Thruster is the standard, rifle-sized configuration of the weapon deployed with Myrmidon and Thallax troops.

Darkfire Cannon


A Darkfire Cannon mounted on a Castellax-class Battle-Automata.

Believed to be of alien origin, though this remains unproven, the Darkfire Cannon is a long, lance-like Photon Thruster Weapon that fires needle-thin beams of dark energy that can pierce even the thickest armour with ease.

Unleashing howling beams of pure darkness, armour, flesh and stone boil away with their touch, and even the most heavily armoured vehicles can be torn apart by their hellish un-light. The Darkfire Cannon was often deployed on the Battle-Automata of the ancient Mechanicum's Legio Cybernetica.


  • The Horus Heresy Book One - Betrayal (Forge World Series) by Alan Bligh, pg. 240
  • The Horus Heresy Book Two - Massacre (Forge World Series) by Alan Bligh, pg. 267
  • White Dwarf 59 (2015), "Forge World - Castellax Battle-Automata with Darkfire Cannon"
  • Forgeworld site - Thallax armed with Photon Thruster
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