Yamatai Mainland Defence Force

The Yamatai Mainland Defence Force is Yamatai's high readiness force deployed to Chisei under the auspices of the Treaty of Mutual Defensive Cooperation, with a primary mission of defence and retaliation against an attack from East Kuiju or Arshavat. It comprises of two main branches, the Ground Defence Force and Air Defence Force, and is designed and equipped to support and work alongside the Chiseian Royal Army and Chiseian Royal Air Force to carry out its mission of deterrence and retaliation.

The YMDF is permanently stationed in Chisei, operating several bases on land leased from Chisei. The peacetime headquarters of the YMDF are located in Eito, while the wartime headquarters are located at Dengaku Airbase.