The Greek form, rendered "devil" in the Authorized Version of the New Testament. Daemons are spoken of as spiritual beings (Matthew 8:16; 10:1; 12:43-45) at enmity with God, and as having a certain power over man (James 2:19; Revelation 16:14). They recognize our Lord as the Son of God (Matthew 8:20; Luke 4:41). They belong to the number of those angels that "kept not their first estate," "unclean spirits," "fallen angels," the angels of the devil (Matthew 25:41; Revelation 12:7-9). They are the "principalities and powers" against which we must "wrestle" (Ephesians 6:12).
These dictionary topics are from M.G. Easton M.A., D.D., Illustrated Bible Dictionary, Third Edition, published by Thomas Nelson, 1897. Public Domain, copy freely.
Easton, Matthew George. "Entry for 'Daemon'". "Easton's Bible Dictionary".