Demons, Daemons and Daimons
The three English words demon, daemon, and daimon all derive from Greek δαίμων (daimôn), the word for a spirit that served as a link between the human and divine spheres. Daimons could be benevolent or malevolent. They were much lower in the divine hierarchy than gods like Jupiter and Diana.
In first century Rome, a good way to make a pagan angry was to refer to all his gods as “daimons.” In Christian writings the word was used to signify “pagan god” or “unclean spirit.” Much later, when the Bible was translated into Old English, “demon” was rendered as “devil.”
One type of “daimon” recognized by pagans was a benevolent spirit, a “guardian angel” that attended the individual from birth to death. This personal “genius” was a kind of soul.
It’s presumably the concept of daimon as soul that underlies the daemons of Philip Pullman’s “His Dark Materials” trilogy. Some of Pullman’s readers were bothered by the pronunciation of daemon as [dē’mən] in the movie The Golden Compass (2007).
Although Merriam-Webster and the OED indicate that both demon and daemon are pronounced the same, I’d guess that many a silent reader has been giving daemon a different mental pronunciation. At least one IMDb commentator declares outright that he plans to pronounce daemon “day-mon” in order to distinguish Pullman’s helpful little soul creatures from malevolent demons.
The word daimon [dī’mōn’], with the meaning of “guiding spirit,” is a latecomer to English (earliest OED citation 1852). With its different pronunciation, daimon stands as a possible alternate choice for writers who want the sense of the word without the confusion with demon. Nevertheless, the spelling daemon has its appeal.