Serapion: A tale of Demonic Possession from the Victorian Era

In a career that spanned a mere three years, Gertrude Barrows Bennett (writing as Francis Stevens) published half a dozen books that came to define the genres that followed on. she is most popularly known as the woman who invented dark fantasy, but on the way she also invented a new, creepier kind of dystopian Sci Fi.
Today, you would call this a tale of trauma-onset schizophrenia, or perhaps a terrible descent into Dissociative Identity Disorder, foretold by genetics. In 1920, the best way ...