The 12th episode in the Armored Core series is Armored Core 4. The games take place in an alternate universe where corporations fight wars and have taken control of the government. Food and energy became scarce as the population grew, widening the divide between the rich and the poor. The situation devolved into anarchy, and the government lost control. People looked to companies to give security. Six businesses fought for dominance and began a full-fledged conflict known as the Nation Dismantlement Conflict. A new order was established, and Pax Economica, a system in which loyalty guaranteed food and safety, was instituted.
Five years after the foundation of the Pax Economica, the player assumes the position of a Raven, a rebel group seeking to oppose contemporary slavery by force. The player takes charge of a massive Mech that is part of a team and may be constructed with available pieces and modified with weapons, paint, and cosmetic options. In 30 missions divided into chapters, the player confronts Mechs from corporations in various locations throughout the planet. New components become available at the end of each level, and the Mech can be repaired with pay. Multiplayer is available through the PlayStation Network and Xbox Live.
