The Collaborative International Dictionary
Demonist
Demonist \De"mon*ist\, n. A believer in, or worshiper of, demons.
Wiktionary
demonist
n. A believer in, or worshipper of, demons.
Usage examples of "demonist".
Your discovery of the dagger on the female led the Inquisition to a nest of preman heretics and demonists hiding in the jail.