The Mainframe is the first core of VOLKNET, the Foehn Revolt's tactical AI. It is located in the Kashmir Home base and secretly houses the final MIDAS warhead originally given to Yunru by Rashidi.
The Kashmir Home base, where the Mainframe is housed, becomes the target of the joint invasion of China by Russia and the Latin Confederation after the capture of the Chinese Military Headquarters in Shanghai, for the purpose of locating Yunru and her Centurion in the battlefield. Confederation forces led by the Soviet General storm the base, take over it from Foehn, capture the Mainframe and attempt to search it, but seconds later, the MIDAS hidden inside it detonates, exterminating the Foehn survivors, the nearby Epsilon forces, and the entire Confederation army including Morales to erase any traces of the Revolt, causing VOLKNET to go online.
In terms of gameplay, the Mainframe blocks the usage of Tactical Nuke in a radius of 10 around itself.
In Thread of Dread, the Mainframe is found inside the massive Foehn base, surrounded by Dragonflies, EMP Mines and Windbelts and heavily guarded by a huge number of defences and Iron Dragons. Although the player is given three objectives (capturing the Mainframe, killing Yunru and destroying the Centurion), only the capture of the Mainframe is necessary to beat the mission as the MIDAS explodes and obliterates everything on the map.