A Medusa Siege Tank dug-in for a siege

The Medusa, also known as the Medusa Siege Tank, is a siege tank used by the Imperial Guard. Like the Griffon heavy mortar carrier, the Medusa is a siege weapon mounted onto a Chimera tank chassis, transforming it into a mobile artillery piece. The Medusa is named after the weapon it carries, the Medusa Siege Gun. During a siege the Medusa is primarily used to breach the walls of enemy fortifications so that the attacking infantry can storm the position and eliminate all resistance. During urban warfare the Medusa can be used as an infantry support vehicle, toppling buildings and walls for the Imperial attackers.

The Medusa is an older weapon of the Imperial Guard, and is slowly losing its place as Imperial military commanders look to better alternatives to serve in the role of siege tank due to the Medusa's lack of range, armour, and ammunition capacity. The Medusa and Griffon have been largely replaced as infantry support vehicles by the Thunderer Siege Tank and the Leman Russ Demolisher Tank. The Basilisk and Manticore are also preferred due to their long-range engagement capabilities. The Medusa is still kept in reserve batteries just in case they are needed, but many Imperial commanders try to avoid using them whenever possible. Still, when an enemy wall needs to be breached or a line of heavily defended bunkers needs to be assaulted, the Medusa Siege Tank can get the job done.


The Medusa Siege Tank was first used by the Imperium during the Great Crusade in the late 30th Millennium, where it was fielded in great numbers by the Imperial Army and Mechanicum, and in smaller numbers by the Space Marine Legions. The Medusa tanks used by the Space Marine Legions were usually crewed by the Legion's mortal personnel, but they were also crewed at times by the Space Marines themselves. The Medusa, along with the Basilisk, saw only limited usage by most of the Space Marine Legions, as the Astartes preferred to use the more versatile Whirlwind artillery tanks, which were based upon the Rhino chassis and thus were easier for the Legions to repair. There were some Legions that made heavier use of the Medusa, such as the Iron Warriors and Imperial Fists Legions, who specialised in conducting or defending against siege warfare. During these ancient times the Medusa could be outfitted in much the same way it is in the late 41st Millennium, but the tank could also take on additional upgrades and attachments which have long since been lost to the Imperium.


A Medusa Siege Tank in urban combat, its crew dangerously exposed

The Medusa Siege Gun serves as this siege tank's primary weapon, and although the tank only carries twenty rounds of ammunition for that gun, it can still be used to great effect against enemy structures. The Medusa also is outfitted with a hull-mounted Heavy Bolter to be used as a defensive weapon against enemy infantry. The Medusa can use several different types of shells, but not as many as the Heavy Mortar Cannon or the Griffon. The Medusa can be upgraded with a enclosed crew compartment, which aids in keeping the crew safe from small arms fire, as well as camouflage netting, extra armour plating, a Hunter-Killer Missile Launcher, improved communications equipment, a mine sweeper, a Pintle-Mounted Heavy Stubber or Storm Bolter, rough terrain modifications, a searchlight, track guards, and a smoke launcher. During the Great Crusade and Horus Heresy in the late 30th and early 31st Millennia, Medusa tanks could be outfitted with other upgrades such as an auxiliary drive system and Pintle-mounted twin-linked Bolters. The Medusa was sometimes also used as a command tank for artillery formations.


  • High Explosive - High Explosive Rounds are the standard shells used by most artillery weapons. These shells are more than capable of destroying infantry units and even vehicles through their sheer explosive force.
  • Siege Shells - Siege Shells are used against enemy structures and fortifications. They are fused to explode after hitting the ground, causing damage to the building's foundation.
  • Bastion Breacher Shells - These shells are fired by the Medusa tank and the stand-alone Medusa Siege Gun. They are fired directly into the enemy walls where they burrow deep and then explode after penetrating, causing the wall to explode outwards and creating a breach for Imperial infantry to enter through.

Regiments Known To Field Medusa Siege Tanks

An abandoned Medusa Siege Tank of the Vraksian Traitor Militia with is troop compartment left open during the Siege of Vraks

  • 8th Valhallan Armoured Regiment - The 8th Valhallan Armoured Regiment made use of the Medusa Siege Tank during the Sallan's World Offensive
  • 28th Death Korps of Krieg Armoured Regiment - The 28th Krieg Armoured Regiment deployed the Medusa Siege Tank as part of the Galan V Expeditionary Force
  • 2nd Palladius Armoured Regiment
  • 101st Tallarn Armoured Regiment
  • 17th Tallarn Regiment - The 17th Tallarn Regiment made use of several Medusa Siege Tanks during the Taros Campaign
  • 122nd Cadian Regiment - The 122nd Cadian Regiment made use of the Medusa Siege Tank during the Siege of Vogen City
  • 13th Cadian Armoured Regiment - The 13th Cadian Armoured Regiment was issued Medusa Siege Tanks when it served as part of the Cadian Gate Garrison Forces during the 13th Black Crusade
  • The Death Korps of Krieg - The regiments of the Death Korps of Krieg used many Medusa Siege Tanks during the grinding Siege of Vraks.
  • The Vraksian Traitor Militia - The Vraksian Traitor Militia, with access to the vast Departmento Munitorum storehouses on Vraks Prime, used many Medusa Siege Tanks during the Siege of Vraks.

Adeptus Mechanicus Technical Specifications

Medusa Siege Tank
Vehicle Name: Medusa Main Armament: Medusa Siege Gun
Forge World of Origin: Gryphonne IV Secondary Armament: Heavy Bolter
Known Patterns: II - XIII Traverse: 3 degrees
Crew: 1 Driver, 1 Commander, 1 Gunner, 2 Loaders Elevation: 0 to 40 degrees
Powerplant: Vulcanor 16 Twin Coupled Multi-Fuel Main Ammunition: 18 Rounds
Weight: 38 Tonnes Secondary Ammunition: 300 Rounds
Length: 5.29 metres Armour:
Width: 3.78 metres
Height: 3.72 metres Superstructure: 100 millimetres
Ground Clearance: 0.45 metres Hull: 150 millimetres
Max Speed On-Road: 50 kilometres per hour Gun Mantlet: N/A
Max Speed Off-Road: 35 kilometres per hour Vehicle Designation: 247-941-3021-BA112
Transport Capacity: N/A Firing Ports: N/A
Access Points: N/A Turret: N/A


  • Imperial Armour, pp. 64-65
  • Imperial Armour Volume One - Imperial Guard & Imperial Navy, pp. 165-170
  • Imperial Armour Volume One - Imperial Guard (Second Edition), pp. 9, 160, 162, 169-172, 263, 267
  • Imperial Armour Volume Five - The Siege of Vraks - Part One
  • Imperial Armour Volume Six - The Siege of Vraks - Part Two, pp. 28, 76
  • Imperial Armour Volume Seven - The Siege of Vraks - Part Three, pp. 126, 134-135, 187
  • Imperial Armour Volume Twelve - The Fall of Orpheus, pg. 204
  • Imperial Armour - The Horus Heresy - Book One: Betrayal, pg. 220

Also See


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