Question:
How do you know if demons are around you?

Answer:

 Sometimes the presence of demons is very obvious (Mark 5:2-15), but sometimes it can be very hard to detect (2 Corinthians 11:14).  Satan can appear as appealing and sly, trying to sway your judgment.  The best way to detect the presence of a demon would be to ask the person what they think of the Lord Jesus Christ.
2 John 1:7 – “For many deceivers are entered into the world, who confess not that Jesus Christ is come in the flesh. This is a deceiver and an antichrist.”