Yes but who is to say that researching demons and stuff can't invite them in to oppress you?
Take note of the adage: Know your enemy.
Now the place to learn what we need to know about Satan is the Bible. We should not learn his practices as in what the occult do to follow Satan. We should learn that Satan is a powerful enemy and we should learn his tricks used against us.
2 Corinthians 2:11 in order that
Satan might not outwit us. For we are not unaware of his schemes.
2 Corinthians 11:14 And no wonder, for
Satan himself masquerades as an angel of light.
As for stories of demon possession, I have heard them and they are just as frightening as the movie The Exorcist. I believe that demons continue to possess people and that the Church has a role to cast the demons out of people. This is not for the faint of heart or the weak in spirit so if you think you are not ready for such a topic, then stay away from it.
As for your concern about being possessed against your will, understand that what Satan does to us is limited by God's authority as Job 1 and 2 teaches. Also study Luke 11:17-26 to see that spiritual kingdoms, each person's soul can not be divided between two, God and Satan. God is stronger than any in the analogy. Satan can not cast out God's Spirit dwelling in the soul of one. God can cast out the demons in people because he is stronger.
Now the warning.
Matthew 7:22 Many will say to me on that day, ‘Lord, Lord, did we not prophesy in your name and in your name drive out
demons and in your name perform many miracles?’23 Then I will tell them plainly, ‘I never knew you. Away from me, you evildoers!’
Satan can enter people in the church.
John 13:27 As soon as Judas took the bread,
Satan entered into him. So Jesus told him, “What you are about to do, do quickly.”
Acts 5:3 Then Peter said, “Ananias, how is it that
Satan has so filled your heart that you have lied to the Holy Spirit and have kept for yourself some of the money you received for the land?
But, Satan can only enter one that has a heart devoted to Satan and not God.
And now more comfort text.
Romans 8:38 For I am convinced that neither death nor life, neither angels nor
demons, neither the present nor the future, nor any powers,39 neither height nor depth, nor anything else in all creation, will be able to separate us from the love of God that is in Christ Jesus our Lord.