Acronym for "private military company", or a corporation that provides various military services. The end of the Cold War saw a rise in the number of retired soldiers, drastic cuts in military spending, and an increase in small-scale conflicts, creating circumstances ripe for the growth of military contractors in the private sector. PMCs not only directly participate in battle, they also undertake a large variety of other military responsibilities, such as logistics, maintenance, and transport operations, acting as strategic and tactical advisers, and overseeing the training and education of local military assets.

It is said that there were over 20,000 PMC personnel and over 60 PMC firms operating in Iraq as of the summer of 2004. It is considered much more cost-effective to use the services of a PMC than to burden the military budget with the cost of maintaining an army and purchasing expensive, high-tech weapons. Furthermore, one of the biggest merits is that PMC personnel killed in action are not regarded as deaths in the line of duty. PMCs are becoming more dominant than official military personnel, and it is not uncommon to find the military to be solely in charge of policy, while PMCs handle the actual operations.

As a result, PMC-spawned "surrogate wars" have spread across the world since the turn of the century. Also known as the 21st century's "surrogate Cold War", the increase of regional conflict and demand for PMCs have helped companies rake in a fortune and gradually increase their military power, while an exodus of retired soldiers has infused them with years of experience. National militaries have slowly weakened as their reliance on PMCs has increased, with 60% of the world's armaments now in the hands of private enterprise. Of the world's five biggest PMCs, two are located in the United States, with the other three located in France, Britain, and Russia. Their clients can be found mainly in America, Europe, Africa, and the Middle East. Profits from PMCs are infused back into the American economy, allowing the country to expand its own battlefield operations. US capital follows the US military wherever it goes, leading to an expansion of American marketplaces. With war as the product, money flows back into PMC hands, and so the cycle continues. Mercenary versus rebel, mercenary versus nation, mercenary versus mercenary... With mercenary wars where troops flock to the highest bidder, stable profit becomes the biggest concern, and the battlefield soon turns into another marketplace driven by greed. With many battlefields left in the hands of PMCs, and states concerned about their own security and profit, PMCs are now an essential entity on the world stage, thus giving birth to the so-called "war economy".

As has been shown with Article 47 of the Geneva Convention, which states that a mercenary is not a legal combatant, the international community would theoretically never allow PMC personnel to directly participate in battle, despite the Kosovo War raising questions about the Convention's role in the modern world. However, the spark that allowed PMCs to increase their activities can be traced to the introduction of the Sons of the Patriots (SOP) battlefield control system. Developed by AT Security, the system ensures that battlefield commanders can micro as well as macro manage every aspect of a war—from individual soldiers to entire deployments—through the use of nanomachines. All military personnel, whether national or private, are injected with nanomachines under the system, with all modern weapons requiring an ID check before they can be used. If the person does not pass the ID check, the weapon is locked and cannot be fired. Personnel cannot so much as board a combat vehicle without ID clearance. With this much destructive power lying free of any national ideology, countries have naturally grown fearful of the strength of PMCs, but in truth, the SOP System is said to prevent any PMC from ever attacking a client.