The devil/satan is called the prince of the air.
        Ephesians 2:2  Wherein in time past ye walked according to the course of this world, according to the prince of the power of the air, the spirit that now worketh in the children of disobedience

        Prince speaks of the exalted position of his 
        rulership.
        Power speaks of the area of his rulership, above 
        and around the earth.

The biblical names of satan identifies his works.
         He is mentioned over 200 times under many names.

Demons are liars like their father, devil/satan, who know no truth.
          John 8:44 Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it. 

Demons work in order.
          Ephesians 1:21 Far above all principality, and power, and might, and dominion, and every name that is named, not only in this world, but also in that which is to come.
           Ephesians 6:12 For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places. 

Demons have their own will.
          Matthew 12:43-44 When the unclean spirit is gone out of a man, he walketh through dry places, seeking rest, and findeth none.
Then he saith, I will return into my house from whence I came out; and when he is come, he findeth it empty, swept, and garnished.

Demons even believe in God.
         James 2:19  Thou believest that there is one God; thou doest well: the devils also believe, and tremble.

Demons know who it is that rebukes and cast them out.
         Mark 1:24  Saying, Let us alone; what have we to do with thee, thou Jesus of Nazareth? art thou come to destroy us? I know thee who thou art, the Holy One of God.
          Acts 19:15  And the evil spirit answered and said, Jesus I know, and Paul I know; but who are you?

Demons vary in wickedness.
          Matthew 12:45 Then goeth he, and taketh with himself seven other spirits more wicked than himself, and they enter in and dwell there: and the last state of that man is worse than the first. Even so shall it be also unto this wicked generation.

The devil will be bound and cast into the bottomless pit.
          Revelation 20:1-3 And I saw an angel come down from heaven, having the key of the bottomless pit and a great chain in his hand.
And he laid hold on the dragon, that old serpent, which is the Devil, and Satan, and bound him a thousand years,
And cast him into the bottomless pit, and shut him up, and set a seal upon him, that he should deceive the nations no more, till the thousand years should be fulfilled: and after that he must be loosed a little season.

Demons on earth in Jesus days are still inhabiting peoples bodies today.
           Matthew 10:1  And when he had called unto him his twelve disciples, he gave them power against unclean spirits, to cast them out, and to heal all manner of sickness and all manner of disease.

                     It is still for today, it is given to all disciples throughout the ages.

The demons that Jesus cast out of people are not in hell.
         Matthew 8:29 And, behold, they [the demons]  cried out, saying, What have we to do with thee, Jesus, thou Son of God? art thou come hither to torment us before the time? 
         Luke 8:31 And they [the demons] besought him [Jesus] that he would not command them to go out into the deep. 

Demons are not spirits of dead people and they are not offspring of angels or men.

Jesus gave His disciple power and authority over all devils.
        Luke 9:1 Then he called his twelve disciples together, and gave them power and authority over all devils. . . .

Evil spirits are liars and may not be telling the truth about their names, numbers or strength. 
          John 8:44  Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it.

Other evil spirits were called foul spirit.
         Revelation 18:2 And he cried mightily with a strong voice, saying, Babylon the great is fallen, is fallen, and is become the habitation of devils, and the hold of every foul spirit..... 

Some evil spirits are seducing spirits.
        1 Timothy 4:1 Now the Spirit speaketh expressly, that in the latter times some shall depart from the faith, giving heed to seducing spirits, and doctrines of devils;

Satan is called an angel of light.
       2 Corinthians 11:14 And no marvel; for satan himself is transformed into an angel of light.

There are evil spirits called familiar spirits.
        Leviticus 20:6  And the soul that turneth after such as have familiar spirits......
        2 Kings 23:24  Moreover the workers with familiar spirits.....

There are also evil spirits called blind and dumb spirits.
         Matthew 12:22  Then was brought unto him one possessed with a devil, blind, and dumb: and he healed him, insomuch that the blind and dumb both spake and saw.

And some other evil spirits are called unclean spirits.
        Luke 9:42 And as he was yet a coming, the devil threw him down, and tare him. And Jesus rebuked the unclean spirit, and healed the child, and delivered him again to his father.

Another evil spirit is named a deaf and dumb spirit.
         Mark 9:25  When Jesus saw that the people came running together, he rebuked the foul spirit, saying unto him, Thou dumb and deaf spirit, I charge thee, come out of him, and enter no more into him.

There are many names in God's Word identifying evil spirits. Jesus used a number of them Himself.

       Luke 13:11 And, behold, there was a woman which had a spirit of infirmity eighteen years, and was bowed together, and could in no wise lift up herself.

The apostles pointed out the demons final doom.
        Matthew 25:41 Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels: 

The apostles have indicated that demons have a home.

         Luke 8:31 And they [demons] besought Him [Jesus] that he would not command them to go out into the deep [bottomless pit].

                 Revelation 9:11And they had a king over them, which is the angel of the bottomless pit; 

The apostles suggested demons were organized under satan.
       Ephesians 6:12 For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places.

The Apostles mention the expulsion of demons from human beings. 
       Luke 9:42 And as he was yet a coming, the devil threw him down, and tare him. And Jesus rebuked the unclean spirit, and healed the child, and delivered him again to his father.