demonism

noun3

1. •
   Belief in, or worship of demons or devils.
2. •
   An act or event attributed to demons or devils; an evil act.

   • So many boys, so many places have disappeared. Blue Gate Fields, scene of many an Asiatic demonism, is gone. — 1919
3. •
   (figurative) The quality of being demonic.

   • What a pitiful horror indeed must that Ypres desolation and desecration be—a baseness of demonism. — 1915