In the year 2030, "The Belian Island Incident" happened where a highly radioactive alien substance was accidentally exposed to the atmosphere, causing half the world's population to be killed or mutated into zombie-like creatures called ELID (Euroky Low-Emission Infectious Disease) and the land becoming contaminated and uninhabitable. In response to the world suffering a shortage of Manpower, highly advanced androids with superior strength and advanced AI capable of expressing emotions called A-Dolls (Autonomous Dolls) were created.
When World War 3 broke out in 2045 to 2051 over uncontaminated land and resources, Private Military Companies used A-Dolls with the ability to fight called T-Dolls (Tactical Dolls) in the war, which made them rich, becoming the de facto police and military of many nations after the war ended. However, in 2061, T-Dolls of the world's largest PMC, Sangvis Ferri, suddenly rebelled, killed their human masters and attack nearby human settlements. In response, Grifon & Kryuger PMC and their T-Dolls were hired to stop and contain the Sangvis Ferri Forces.