The Volcano Cannon is the one of the most powerful ground vehicle-mounted Laser Weapons in the Imperium's arsenal. Developed long ago during the Dark Age of Technology, the "Volcano" Cannon (so named, it is generally thought, given its tendency to turn rock and stone into spraying magma where it strikes) is an apocalyptically powerful laser weapon designed to level the most reinforced fortification and deal fatal blows to the most colossal of enemy war machines. Such targets include other Titan-sized opponents, such as Ork Gargants, reinforced strong points, and even minor Hive Cities. Imperial Warlord-class Titans can be equipped with two Volcano Cannons, one on each of its weapon arms, and the Imperator-class Titan can be equipped with up to a total of six on its carapace mounts. The Warhound-class Titan and Reaver-class Titan's plasma reactors are too small to effectively power a Volcano Cannon. Originally developed for use on numerous classes of Imperial Titans, Volcano Cannons were later adapted to be mounted upon the powerful Falchion Super-Heavy Tank Destroyer, as well as the Shadowsword super-heavy tank, albeit this resulted in slightly shorter range. Of course, it is not only the Imperium's Titans that dominate the battlefield with such a weapon; those who have turned traitor and fight alongside the forces of Chaos put it to more diabolical use, incinerating Hive Cities or burning entire Imperial regiments. Chaos Titans that are in service to the Dark Mechanicum can also be equipped with these powerful weapons if they are of the appropriate class, like their Loyalist counterparts.
In the 41st Millennium, the Adeptus Mechanicus sanctioned model of the Volcano Cannon is the MkIV Phaeton pattern, which was perfected by mid-M35, and is denoted by the astonishing white light of the laser. In contrast, the MkIII Synne pattern Volcano Cannon produces an orange-yellow laser akin to the solar flare of a dying star. The original Mk I variant generated a powerful red beam, truly like a river of lava in the night, though it proved almost as volatile as the unsuccessful MkII Teracharge Volcano Cannon. This was said to be even more powerful than the current MkIV, but was never used in service as it almost invariably destroyed the arms of the Titans and hulls of the tanks that carried it. Once the current stable model had been created, it began to be manufactured in small numbers on just a handful of forge worlds in addition to Mars. These included Estaban III, Phaeton and Gryphonne IV, all of which are surrounded by formidable Imperial defences. Production was necessarily limited due to the complexities and inherent dangers involved in working with rare volatile crystals. Many within the Administratum preferred that knowledge of the weapon's construction be kept limited to safeguard it from the attentions of vile xenos and insidious traitors.
It is well known that a single blast from the Volcano Cannon is capable of crippling a Titan or reducing a tank to a pile of molten scrap. Because of such potency, before the weapon is fired on a Shadowsword, the vehicle's engine must be disengaged so power can be transferred accordingly. Likewise, the capacitors will be thoroughly drained as a result of expanding vasts amounts of energy, so must be recharged before the vehicle can move again. Such a sacrifice of mobility for using the Volcano Cannon means that a Shadowsword must be well protected or skillfully maneuvered at all times. Among the crew of every Shadowsword is a Tech-Priest Enginseer, who enacts the necessary binary prayers and technical processes while tending to the crystal in order to fire the Volcano Cannon successfully. His cold, machine-like presence and weeping cybernetics ensure that he is never fully accepted by the rest of the crew, but his dedication to the Shadowsword's machine spirit keeps the vehicle firing in the heat of battle, so his loyalty will never be questioned.
The Volcano Cannon produces a highly volatile but condensed laser beam. Once the weapon's capacitors are fully charged, this beam passes through a flawless crystal, each of which is taken from a mineral vein that lies beneath lava rivers on Cinderus XI. It is said by the Magos Geologis that several thousand heretic psykers were slaughtered and buried here for taking part in a traitorous plot to kill Cinderus' Planetary Governor. Their remains had been compressed unusually quickly by the shifting geological structures and combine with the natural elements present beneath the lava to form a unique crystalline mineral. It remains highly unstable, but its light-affecting properties were discovered to be useful to the servants of the Emperor.
When the cannon's beam connects with an armoured target, it overwhelms it with energy, tearing away armour and reducing it to molten slag; then causing the victim to overheat and explode within fractions of a second. Any flesh or biomatter touched by the beam is instantly vaporised into a mist of superheated ions. Though it typically creates a concentrated mid-frequency drone upon firing, it is not uncommon for the surrounding air to be filled with a high-pitched crackling. This violent noise, clawing at the minds of those who serve frequently beside the vehicle, has been thought to induce insanity. Some even claim to hear the final screams of the dead psykers, though the tank or Titan crews themselves remain have never been reported to suffer from these ill effects. As a consequence of these claims, units of infantry escorts are subject to periodic psychometric purges. The Imperium sees this as an acceptable price to pay for deploying such a weapon on the battlefield.
Notable Volcano Cannon Variants
- Belicosa Pattern Volcano Cannon - During the Great Crusade and Horus Heresy eras, the Belicosa Pattern Volcano cannon was one of the most potent energy weapons produced by the forges of the Mechanicum, short of the continent-razing guns mounted on the warships of the Imperialis Armada. It was a weapon so fearsome that only the plasma reactor of a mighty Warlord-class Titan could feed its ravenous appetite for power and make possible its destruction of the most terrible foes of Mankind.
- Adeptus Titanicus: Rulebook
- Imperial Armour Volume One - Imperial Guard and Imperial Navy, pp. 91-98
- Imperial Armour Apocalypse, pp. 6, 124
- Imperial Armour, pp. 22-23, 37
- The Horus Heresy - Book Three: Extermination by Alan Bligh, pg. 241
- Warhammer 40,000: Munitorum - Volcano Cannons (Digital Edition)
- Forge World - Mar Pattern Warlord Titan Belicosa Pattern Volcano Cannon
- Forge World - Reaver Titan Volcano Cannon