In this book we will discuss the origin of evil spirits, how they are divided their classes. The traditional church calls all spirits demons and devils, but this is not the right language. To affirm this thesis, we must go to biblical and extrabiblical content to know the classes of spirits that have molested humanity since the beginning of time, let us talk here about the primary source, the fallen angels, right after the evil spirits, and demons or devils with their classifications and performances. No fallen angel is a demon, no demon has ever been a n. n. Let us talk about the fallen angels, who are usually the principalities and spiritual powers of this fallen world, the evil spirits who are obsessives, and the demons or devils, who usually feed on the vital energy of humans. These are themes that the reader needs to have an open mind because it will mess with beliefs rooted in centuries in the Christian environment.