The Guillotine Gun was a specialized ranged weapon which combined a mortar grenade launcher with an axehead on the end of the barrel. The end result was an extremely lethal weapon capable of annihilating entire groups of enemies from long range whilst also offering some form of melee weapon.
The weapon was utilized by the raiders under the command of Philippe Rose in Saint-Denis, during their attempt to recover an artifact known as the Head of Saint Denis from the catacombs beneath the Basilica of Saint-Denis, on the orders of Napoleon Bonaparte. However, the weapon was stolen by a young orphan named Léon, and given to French Assassin Arno Dorian during the latter's exploration of the catacombs. Arno then fired it into a group of raiders, killing them all.