The Legacy by Jere Cunningham (1977): That Demon Life Got Me in Its Sway

You might or might not be familiar with the name Jere Cunningham, a writer who published several horror paperbacks during the classic vintage era but who moved on to Hollywood screenplays later in his career (couldn't turn up a photo of him anywhere, only an illuminating interview, and I'm never sure if the name "Jere" is pronounced "Jare" or like the standard spelling "Jerry"). Not to be