The Black Brotherhood is a a fanatical cult-like group of international terrorists dedicated to hastening the return of the Great Old Ones and they are one of the many antagonistic groups featured in the Cthulhu Mythos genre by author H.P. Lovecraft.
The Brotherhood which is indeed a dangerous secret society, is made up of people from all ethnicities and all walks of life, and, believing that the Great Old Ones themselves will awaken soon and be among mortals.
The cult's membership is but unclear and well hidden.
They conduct covert operations, such as attempted political assassinations.
They operate in many countries around the world such as the United States, the United Kingdom, Brazil, Japan, China.
Their acts go unquestioned and unnoticed.
Few of its members are taken alive for interrogation, however, as most die shortly after carrying out their operations.