Following the Synchronized Global Default in 2044, the Sustainable War became the only way for the G4 nations to keep their economies functional. The Default also had the side-effect of creating countless destitute raiders, who risked their lives amid the Sustainable War to eke out a living or wreak vengeance against those whom they blamed for their poverty, the "one-percenter" elites who continued enriching themselves through the war.

In 2045, the mercenary unit GHOST was hired to guard a city in California from raider attacks. GHOST was formed by Motoko Kusanagi and other members of the former Section 9 as a way to continue using their military skills to make a living through the Sustainable War after Section 9 was disbanded.