The Bible teaches that demons are real. It speaks about their origin, nature and works.
Demons were originally like the other angels of God with the same attributes and positions as the good angels. When Satan rebelled against God, a portion of the angels participated in his rebellion. God cast them out of Heaven, along with Satan. They were no longer good spiritual beings (angels). They became evil spiritual beings.
If demons are not “fallen” angels, then we have no other Biblical explanation for their existence. Satan cannot create his own forces, because all things were created by God. There are two groups of these fallen angels. One group is actively opposing God and His people on earth.
The demons know their final destiny is a place of eternal torment. Since hell is a place of torment and was prepared for Satan and his angels, then demons must be the fallen angels.
Throughout the Bible, demons are shown as active on earth. Since Satan is not omnipresent (present everywhere), he uses demons to do his will and accomplish his purposes throughout the world. They constitute the “powers of the air” (Ephesians 2:2) and the “powers of darkness” (Colossians 1:13) and are all under the control of Satan.
These demons attack unbelievers driving them to commit terrible evil acts, to murder, injure, commit suicide, etc. They affect the mind with emotional problems and the body with physical infirmities. Demons attack believers through temptation, deception, depression, and oppression. They try to keep them in bondage to negative habits and fear. They accuse and slander and create division among the people of God. They target the spiritual walk with God and fight against the Word of God, the worship of God, and work for God. They also attack the physical body. Unbelievers are defenseless against the attacks of demonic powers, but believers have powerful spiritual weapons and strategies for dealing with this mighty spiritual force of evil.
God wants his people to wear the spiritual armor. They must constantly be at war with these demonic forces using the spiritual weapons. Let’s strive to have this skill of spiritual warfare by God’s grace because the demons are real.