Answer
The Derg, led by Mengistu Haile Mariam, is estimated to have killed between 500,000 and 2,000,000 Ethiopians during its reign from 1974 to 1991. The Derg's human rights abuses included political repression, torture, arbitrary detention, and extrajudicial killings. The Derg's reign also saw the outbreak of the Ethiopian Civil War, which resulted in the deaths of an estimated 1.5 million people.