Demons are very intelligent creatures.They are spirits,and do not normally have physical bodies allthough they can,for certain period of time manifest s a physical body that we can see and feel.They were once angels in God's service.Satan,their leader was once an arch angel.He is one of the most powerfull and intelligent creature God ever createad.Mans intellegence is nothing compared to satans.Many,many ages ago satan chose to rebel against god and try to exault himself abouve God.                                   A large number of angels followed satan to be in his service instead of God's.These angels are often referred to as "FALLEN ANGELS" and are the various demons.They are all evil and liers.They go by different names in various parts of the world.The number and various types of demons are so vast that we could never name them all.Also,the same demon will take different names depending on what geographical area he is in.Satans kingdom is highly organised and very very efficient.They have a wide range of strength and abilities and can be defeated only with the power of God.In God we are in a remarkable position of authority over demons and we should make use of that authority because the eternal god is our refuge.