Not as whether there are demons in reality because the world around what is filled of so many evil.
The very presence of evil in this world is an expression of presence of the muscle demons are the ones influencing the human behavior. There are demons everywhere what could make a very good and perfect world God created to become a den of evil and goodness. These spirits are demons they are in the world.
We should avoid being the abode of demons they must use human citizens to equip most of their missions so those who are practicing are directly serving the devil. Demons can take up human form or whatever kind of treatments what they want to.
We should not live a careless life we must understand that there are demons who want to have their evil plans executed in our lives so we must be very careful of this.