The Black Castle is a novel written by Les Daniels. It was first published in 1978.
Description[]
Spain, 1496. The Inquisition. Screams. And the darkness that is Europe is lit by the human bonfires of the Inquisition. Even those cold and courtly agents of the Dark One. Don Sebastian and his witch consort Margarita, are sickened by the sound of cracking bones. Even they are moved to try and stop this inhuman horror. But even they -- who soar on leather wings and fill their bowls with blood -- cannot escape the fiery lash of Don Sebastian's own brother, the Grand Inquisitor...