It should also be noted that the word “demon” also comes from the Greeks. Plato derives it from daemon, an adjective formed from dao and signifying “knowing” or “intelligent”. In the Homeric period, daimon was synonymous with “god”( θεος). ... Homer and the earlier poets used the term gods and daimones for the same beings.

In post-Homeric usage(Hesiod and the philosophers), demons are conceived of as intermediaries between the gods and men! Plato asserts that, “The deity has no intercourse with man; but all the intercourse and conversation between gods and men are carried on by the mediation of demons”(Symposium 202-3) The view also finds expression that every man from his birth is accompanied by a special daimon. Attic writers, especially, make reference to agathos daimon (a good demon).

As time went on, the Greeks began to view demons as morally imperfect beings, like man, some good, some evil. This step in the gradual lowering of the concept of the word was the result of an effort to exalt the gods and make their intermediary “demons” responsible for the passions and scandals attributed to them in popular mythologies. Plato’s disciple Xenocrates was the first to distinguish expressly between good and evil demons, however even the good demons had imperfect moral purity. 

This distinction was especially coninued by the Stoics. Plutarch attributes degrees of virtue to them (De Defectione Oraculorum XIII). The Stoic philosopher Posidonius (1st c. BCE) viewed demons as spirits of the departed, good and evil, with the purer inhabiting the higher regions and the impure remaining nearer the earth.

Finally, with the Septuagint, New Testament and early Christian writings, all demons are evil and members of Satan’s kingdom. The expressions daimon and daimonion are not found very frequently in the greek Old Testament, yet they are employed to translate certain Hebrew words. It is to be noted carefully that Hebrew possesses no precise equivalent for the Hellenistic Greek terms daimon or daimonion. Indeed, no fewer than five different Hebrew words are translated by it.