Brood of the Witch-Queen

"Brood of the Witch Queen" is a 1918 supernatural novel by Arthur Henry Sarsfield Ward, known better under his pseudonym, Sax Rohmer. The story deals with Robert Cairn and his suspicions of Antony Ferrara, the adopted son of an old friend and colleague of Robert's father, Dr Bruce Cairn, of infernal magic and supernatural influence. (Excerpt from Wikipedia)