Marinebrigade Ehrhardt
The O.C. was created in 1920 by Captain Hermann Ehrhardt and some of his followers in the Marinebrigade Ehrhardt. They had been hiding out in Bavaria following the forced disbandment of Freikorps organizations after the Kapp Putsch of March 1920. His fighters had formed the Association of Former Ehrhardt Officers which then became the O.C. The founders used Freikorps contacts to recruit members in dozens of cities and small towns all over Germany. Eventually it came to have districts encompassing large swathes of the nation. They were particularly active in Berlin, where many of their crimes were committed. The O.C. had about 5,000 personnel.