Knightmare Frame is a mechanical, often humanoid war machines, suit that makes extensive use of Metatron-based technology. Kinghtmare Frames were developed and are most often used by the Holy Britannian Empire, who use it to the extent such that most people who encounter Knightmare Frames in general believe one to be owned by the organization. Unveiled during the invasion of Japan, Knightmare Frames are almost exclusively used in place, and sometimes on par with the practically obsolete main battle tanks. The name "Knightmare Frame" is a play on the word nightmare and a knight's mare. There also exists a derivative type of war machine based on the Knightmare Frames called Knight Giga Fortress.