The Rapier is a semi-automated tracked weapon mount that is used by both the Imperial Guard and the Adeptus Astartes as a mobile heavy weapons platform that can transport weapons that are too heavy for a single Guardsman or even a Space Marine to carry on his own. The Rapier is similar in appearance and operation to the Space Marine Thunderfire Cannon, and features on-board targeting systems and power generators. The Rapier can be operated by a single operator or by a pair of operators who control both the device's movement and weapons fire from the controls at the rear of the mount. The Rapier can be controlled by either a Tech-priest or a Techmarine, or by specially-trained Imperial Guardsmen and Space Marines. While the Rapier's Machine Spirit is capable of moving the Rapier on its own, its weapons cannot be fired without input from its operator.
The device is usually armed with a set of quad Heavy Bolters for anti-personnel use or a Laser Destroyer Array for anti-armour use. The machine can also be armed with a Quad Mortar, or Thudd Gun useful for siege warfare or suppressive fire. Rapiers could also be armed with even more exotic weaponry for special operations, such as a Graviton Cannon. This now-rare weapon can trace its origins back to the Great Crusade of the 30th Millennium where it was used by both the Imperial Army and the Space Marine Legions against the enemies of the newly-formed Imperium of Man, and later by both sides during the Horus Heresy of the early 31st Millennium.
- Imperial Armour Volume One - Imperial Guard (Second Edition), pg. 267
- The Horus Heresy - Collected Visions
- The Horus Heresy - Book One: Betrayal, pp. 109, 179, 201
- The Horus Heresy - Book Two: Massacre
- Warhammer 40,000: Compendium (2nd Edition)
- Warhammer 40,000: Wargear (2nd Edition)
- Forge World - Space Marine Rapier Laser Destroyer
- Forge World - Imperial Guard Rapier Laser Destroyer
- Forge World - Legion Rapier with Quad Heavy Bolters
- Forge World - Legion Rapier with Graviton Cannon
- Forge World - Legion Rapier with Laser Destroyer