Demons in the Talmud
(ו) אִם־יִתָּקַ֤ע שׁוֹפָר֙ בְּעִ֔יר וְעָ֖ם לֹ֣א יֶחֱרָ֑דוּ אִם־תִּהְיֶ֤ה רָעָה֙ בְּעִ֔יר וַה' לֹ֥א עָשָֽׂה׃

(6) When a ram’s horn is sounded in a town, Do the people not take alarm? Can misfortune come to a town If the LORD has not caused it?

אמר אביי אינהו נפישי מינן וקיימי עלן כי כסלא לאוגיא

Similarly, Abaye said: They are more numerous than we are and they stand over us like mounds of earth surrounding a pit.

תניא אבא בנימין אומר אלמלי נתנה רשות לעין לראות אין כל בריה יכולה לעמוד מפני המזיקין

In another baraita it was taught that Abba Binyamin says: If the eye was given permission to see, no creature would be able to withstand the abundance and ubiquity of the demons and continue to live unaffected by them.

אמר רבא האי דוחקא דהוי בכלה מנייהו הוי הני ברכי דשלהי מנייהו הני מאני דרבנן דבלו מחופיא דידהו הני כרעי דמנקפן מנייהו

Summarizing the effects of the demons, Rava said:
The crowding at the kalla, the gatherings for Torah study during Elul and Adar, is from the demons;those knees that are fatigued even though one did not exert himself is from the demons; those clothes of the Sages that wear out, despite the fact that they do not engage in physical labor, is from friction with the demons; those feet that are in pain is from the demons.

“If we had a keen vision and feeling of all ordinary human life, it would be like hearing the grass grow and the squirrel’s heart beat, and we should die of that roar which lies on the other side of silence.” George Eliot - Middlemarch

האי מאן דבעי למידע להו לייתי קיטמא נהילא ונהדר אפורייה ובצפרא חזי כי כרעי דתרנגולא האי מאן דבעי למחזינהו ליתי שלייתא דשונרתא אוכמתא בת אוכמתא בוכרתא בת בוכרתא ולקליה בנורא ולשחקיה ולימלי עיניה מניה וחזי להו ולשדייה בגובתא דפרזלא ולחתמי' בגושפנקא דפרזלא דילמא גנבי מניה ולחתום פומיה כי היכי דלא ליתזק רב ביבי בר אביי עבד הכי חזא ואתזק בעו רבנן רחמי עליה ואתסי:

One who seeks to know that the demons exist should place fine ashes around his bed, and in the morning the demons’ footprints appear like chickens’ footprints, in the ash. One who seeks to see them should take the afterbirth of a firstborn female black cat, born to a firstborn female black cat, burn it in the fire, grind it and place it in his eyes, and he will see them. He must then place the ashes in an iron tube sealed with an iron seal [gushpanka] lest the demons steal it from him, and then seal the opening so he will not be harmed. Rav Beivai bar Abaye performed this procedure, saw the demons, and was harmed. The Sages prayed for mercy on his behalf and he was healed.

A Few Demons
Foreign gods are called shedim (Deut. 32:17; Ps. 106:37; cf. I Cor. 10:20), rendered "demons" or "devils" in most translations. The word is related to Akkadian šêdu ("demon"; good or evil).
SEʿIRIM ("hairy demons, satyrs") is also applied contemptuously to foreign deities (Lev. 17:7; II Chron. 11:15). These creatures haunt ruins, along with Lilith (Isa. 13:21; 34:14).
LILITH (Isa. 34:14; ultimately from Sumerian lil, "air," not Heb. layl(ah), "night") was originally a succubus, believed to cohabit with mortals, but in the Arslan Tash incantation quoted above she is identified with the child-stealing demon, a character she retains in later folklore. The tradition that the name means "screech-owl" (in so many translations) reflects a very ancient association of birds, especially owls, with the demonic.
MAVET (Mawet), the ordinary Hebrew word for death, is also the proper name of a Canaanite underworld god (Mot), the enemy of Baal in a Ugaritic epic. The proper name, not the common noun, should probably be understood in Isaiah 28:15, 18: "We have made a covenant with Death," and Jeremiah 9:20 [Eng. 9:21]: "For Death is come up into our windows" (cf. Hos. 13:14; Job 18:13, "the firstborn of Death"; 28:22).
RESHEPH is another major god of the Canaanite religion who becomes a demonic figure in biblical literature. Resheph is known as the god of plague over much of the ancient Near East, in texts and artistic representations spanning more than a millennium from 1850 B.C.E. to 350 B.C.E. In Habakkuk 3:5, YHWH on the warpath is said to be preceded and followed by respectively Dever and Resheph. (This is similar to the picture of two divine attendants who escort major gods in ancient myths.) Just as some other names of deities are used as common nouns in biblical Hebrew (Dagon (dagon, "grain"); Ashtaroth (ashtarot, "increase [of the flock]"), etc.) so Reshef (reshef) has come to mean simply "plague" (Deut. 33:29; Ps. 78:48), and the fiery darts of the bow (Ps. 76:4 [Eng. 76:3]; Song 8:6), apparently from the common association of plague and arrows.
DEVER ("Pestilence") is the other demonic herald who marches with YHWH to battle (Hab. 3:5). Dever is also mentioned in Psalms 91:5–6: "Thou shalt not be afraid for the Terror (Paḥad) by night; Nor for the Arrow (Ḥeẓ) that flieth by day; Nor for the Pestilence (Dever) that walketh in the darkness; Nor for the Destruction (Ketev) that wasteth at noonday." Not only Dever but also the other words italicized above have been plausibly identified as names of demons. The "Arrow" is a familiar symbol in folklore, for disease or sudden pain, and Ketev (Qetev; cf. Deut. 32:24; Isa. 28:2; Hos. 13:14) is in this instance the personification of overpowering noonday heat, known also to Greek and Roman demonology.
AZAZEL (ʿAzʾazel) occurs in the ritual for the Day of Atonement (Lev. 16:8, 10, 26). Aaron casts lots over two goats, and the one "for ʿAzʾazel" is presented alive before the Lord, and then released into the wilderness. The ancient Greek and Latin versions understood ʿAzʾazel as "goat that departs," hence "the scapegoat" of some English versions. Most of the rabbinic commentators and some moderns take Azazel as the name of the place to which the goat is driven. The great majority of moderns regard Azazel as the personal name of a demon thought to live in the wilderness.