Damascus Gear: Operation Osaka

Atsuga Corporation's GEAR System introduced piloted humanoid robots in the mid-21st century and transformed every major industry. During World War IV in 2050, every GEAR on Earth simultaneously went berserk and began massacring the population. The survivors of these "RAGE" units drove humanity underground and held the surface for over fifty years. After decades of fighting, humanity retook Japan. Thirty years later, the city of Cosmopolis built on the ruins of Osaka still runs on GEAR technology — and the best pilots fight daily in the Arena for Eyn, reputation, and survival.