The Integrated Staff Headquarters exists to coordinate cross-domain national defence efforts and also serves as the main point of contact between the civilian government and the Yamataian military. The Yamataian Minister of Defence is the chairman of the Integrated Staff Headquarters, and reports directly to the Prime Minister of Yamatai, who is the commander-in-chief according to the Yamataian constitution. The military section of the Integrated Staff Headquarters has operational control over all military and national security personnel of Yamatai's armed forces, with the chain of command running from the Prime Minister and the Minister of Defence to the service branch heads within the Integrated Staff Headquarters, who in turn directly command the Operational Commands of the service branches. The Minister of Defence also serves as the Chairman of the Integrated Staff Headquarters.
Founded in 2021 with the merger of the previous General Department of National Defence and the National Emergency Council, the Integrated Staff Headquarters is headquartered in the Kokubō Sōshō Complex in Heian. The Integrated Staff Headquarters is also known informally as the "ToSa Honbu" or the "Kokubo Sosho".