Firearms came into being over two hundred years ago, during the height of the empire, rising alongside the growing industrialization. Though advances have been made since then, it has been slow owing to tradition, the decline of the empire, and outright suppression.
The gun was invented in the empire, and the imperial administration, recognizing its power, have done everything they could to ensure that nobody else would get it. The construction of firearms have been the monopoly of a few crafting guilds by imperial law, and the design and construction of the gun, and more-so the recipe of the gunpowder, has been a closely guarded secret. As the empire declined, the secrecy and monopolies meant that the gun makers became conservative, and not only was innovation difficult to achieve with so few gun smiths, but often it was opposed by the masters of the guilds.
With a monopoly on firearms the armies of the empire has remained relatively strong despite declines in men, training and equipment. But such things could not last. In the current day the secrets of gun making has leaked from the empire's grasp. Neighboring countries and internal rebels have small-scale gun making industries of their own, and guns have spread from being a strictly military weapon, illegal for civilians to own, to a weapon which can be owned by any with the necessary money.
It is still illegal for any but the designated crafting guilds to produce weaponry, and no imperial citizen may gather a force armed with firearms. While rebel factions out in the empire has done so, the city is too close to the imperial center of power for any to do so. While some nobles and enclave leaders have tried to arm forces with firearms produced in secret factories, they have always been discovered and dealt with harshly by the imperial army.
But individuals may own firearms under imperial law. All that is required are that they possess the papers of crafting that follow with guns sold by the imperial gun smiths. But even this simple requirement is often flaunted by individuals. Few enclaves outside of the imperial administration will ask for the paper of crafting, and they are easily forged. A flourishing black market exists in guns produces by foreign powers or liberated from their former owners. Military long arms are rarely sold to civilians, and thus find buyers on the black market. Also, there are fewer restrictions on innovation among foreign gun smiths, and so designs have begun to appear that are superior to the imperial designs. These too are found on the black market, though ownership is punished severely by the imperial administration.
When speaking in terms of the Fantasy craft rules, the Military pistol, Blunderbuss, Hand Cannon, Harquebus, Musket and Musketoons are considered imperial firearms. The muskets and musketoons are rarely sold to civilians, while both the Hand cannon and Harquebus are considered obsolete. Experimentation into Dueling pistols, Pocket pistols and Long rifles are conducted by foreign gun smiths, as are various customization options, including making the firearms reliable. The light and heavy cannon are also available, but are strictly military weapons.