They do not occupy space as we do.  Many can inhabit a person.-Mark 5:8-9- “For he said unto him, Come out of the man, thou unclean spirit.  And he asked him, what is thy name? and he answered, saying, My name is legion: for we are many.”  A Legion was known as 6826 soldiers etc. They can inhabit animals. - Mark 5:13-14- “And forthwith Jesus gave them leave. And the unclean spirits went out, and entered into the swine: and the herd ran violently down a steep place into the sea, and they were about two thousand; and were choked in the sea.”

It seems that God can send evil spirits to do His will. Judges 9:23- “Then God sent an evil spirit between Abimelech and the men of Shechem; and the men of Schechem dealt treacherously with Abimilech. 1Sam. 16:14- “But the spirit of the Lord departed from Saul, and an evil spirit from the Lord troubled him.” Also, the biggest one of them all is the time where God sent Satan himself to attack Job. Job 1:6-12. God is the one who brings up His servant Job, to Satan. God is in complete control even of what seems bad.

They know the people who cast them out. Acts 19:15- “And the evil spirit answered and said, Jesus I know, and Paul I know; but who are ye?” Mark 1:23-25They are very strong- Acts19:16-“And the man in whom the evil spirit was leaped on them, and overcame them, and prevailed against them, so that they fled out of that house naked and wounded.”
They get tired. - Matt.12:43- “When the unclean spirit is gone out of a man, he walketh through dry places, seeking rest, and findeth none.”

Can cause to be mute and deaf. - Mark 9:17- And one of the multitude answered and said, Master, I have brought unto thee my son, which hath a dumb spirit. (mute) Verse25 “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.”

They can cause weakness.-Luke 13:11-13 “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. And when Jesus saw her, he called her to him, and said unto her, Woman, thou art loosed from thine infirmity. And he laid his hands on her: and immediately she was made straight, and glorified God.”

Demons Can Possess:

Objects/Places

Houses

People

Animals

Demons are liars:  (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 must not be believed.  This scripture is clear to say that what they say cannot be trusted.  To those who consult spirit guides and other forms of spirit communication, you are running a great risk of being deceived.

They get tired: (Matt. 12:43) “When the unclean spirit is gone out of a man, he walketh through dry places, seeking rest, and findeth none.“  A tremendous battle occurs when a spirit goes out of someone and that causes them to get tired.  They have used all their energy in trying not to be expelled, and get tired.  In order to take over the person again, they need help. 

This is why many demonic hauntings start out mild and then build to violent activity.  It gains strength over time.  Getting it while it is weak is the thing to do when the activity first starts to occur.  When it returns, it is still weak and has yet to gain strength to dominate the occupant.  Sometimes repeat cleansings are needed to totally be rid of demons.  They don’t give up very easily.  They receive energy from fear and trauma and want to keep that energy if they can.

They have willpower:  (Energetic Determination) (Matt. 12:44)  “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.“  He says “Iwill”.  The demon has the ability to determine whether or not it wants to return.  The bible says he “will”. 

They vary in wickedness:  (Matt.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.“  This shows not only that they vary in wickedness but in rank and power as well, as this entity was able to gather them showing he was powerful enough to order it to occur.

They know the names of those with power over them:  (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 ye?“  They are very aware of the fact that there are people with authority to cast them out.  (Mark 16:17)  “And these signs shall follow them that believe; In my name shall they cast out devils“  So it is today for all who believe.  They will cast out devils.

They believe and tremble:  (James 2:19)  “Thou believest that there is one God; thou doest well: the devils also believe, and tremble.“  The demons believe and tremble.  They know there is a God.  They know His power.  They know the authority that belongs to them that belong to Christ.  They tremble. And for good reason.  The believer does not need to tremble.  Demons do.

They are highly organized:  (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.“  In this verse, it says “us”.  There were anywhere from 2000 to 5000 entities in the demoniac of Gadera.  They organize themselves for a specific purpose.  And do not occupy space as we do.  (Eph.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.“

They are subject to Christ:  (IPeter 3:22) “Who is gone into heaven, and is on the right hand of God; angels and authorities and powers being made subject unto him.“  Demons know they are under the authority of Christ and to those whom Christ has given authority to.  If you do not possess this, do not fight demons.  You will lose. 

They can perform the gift of fortune telling or psychic power. Acts 16:16-“ And it came to pass, as we went to prayer, a certain damsel possessed with a spirit of divination met us, which brought her masters much gain by soothsaying.”

They have doctrines:  (ITim 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.“  Anything that is taught outside of God’s realm is a demonic doctrine.  Jesus said, “I am the way, the truth and the life, no one comes to the Father but by me.”  (John 14:6)   To go outside of this realm is opening ones self up to demonic doctrine. 

Many times demons will manifest themselves and answer prayers in an attempt to deceive.  The only real answers are in the word of God.  If one goes outside of that realm, they can run into danger and God will set His face against that person.  (Lev.20:6)  “And the soul that turneth after such as have familiar spirits, and after wizards, to go a whoring after them, I will even set my face against that soul, and will cut him off from among his people.“ 

You do not want to be cut off from God or fall into His hands when He is angry.  (Heb.10:31) “It is a fearful thing to fall into the hands of the living God.“  Going outside of Gods realm makes Him very angry because He wants to be your source for power and guidance.  Not demons. 

True disciples are given divine authority over demons:  (Luke 9:1) “Then he called his twelve disciples together, and gave them power and authority over all devils, and to cure diseases.”  If you are a disciple of Christ, you are not consulting psychics, spirit guides, tarot cards, or other forms of demonic divination.  (Matt.10:1,8) “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. 

Heal the sick, cleanse the lepers, raise the dead, cast out devils: freely ye have received, freely give.”  If anyone charges for what they do in deliverance, run!  (IITim.1:7) “For God hath not given us the spirit of fear; but of power, and of love, and of a sound mind.”  Demons are the ones who should fear a saint of God Almighty.   (James 4:7) “Submit yourselves therefore to God. Resist the devil, and he will flee from you.”  To flee means, run in terror.  Let him run!  Both do not need to be afraid.

Be Not Ignorant:  (IICor.2:10-11)  “  To whom ye forgive any thing, I forgive also: for if I forgave any thing, to whom I forgave it, for your sakes forgave I it in the person of Christ;  Lest Satan should get an advantage of us: for we are not ignorant of his devices.”  Unforgiveness can open you up to satanic attack.  Do not let him have an advantage over you!