Angels and demons are vital parts of all religions, especially Abrahamic theologies. (Abrahamic theologies are those that are based on the Old Testament, including Christianity, Islam and Judaism.) Both angels and demons are said to be intelligent spiritual entities that have never lived on earth in human form. They exist exclusively in Spirit, but can manifest in our material world under the right conditions. The question of whether angels and demons actually exist is one that neither I, nor any living person can categorically answer.
Emanuel Swedenborg denied that there was a satanic lord of the underworld. He said that all angels and demons (Swedenborg called them “devils”) were simply the souls of people who once lived on earth. Many mediums, both modern and those of the nineteenth century held (and still hold) the same belief. This is a valid viewpoint. There have been many thousands of very saintly people over the centuries who would be good candidates for angelic status after their deaths. Likewise, there are huge numbers of once living criminals who committed such evil acts that it would be easy to see them as actual devils. Perhaps a few of them decide to become “the baddest dude in Hell”. Then they might qualify as the equals of the legendary Satan.
Thus, it is quite possible that the entire concept of angels and demons is the result of an accumulation of ancient religious dogmas resulting from myriad historical experiences with evil minded human ghosts and their natural adversaries. It’s not an argument I can enter into. No one has any first-hand knowledge of the ancient, pre-human history of the spiritual realm.
However, whether your position on the existence of primordial spirits, there is a great deal of evidence from recent and ancient history demonstrating the existence of demonic entities. All major religions employ exorcists who call upon God, Jesus, Mohammed or other spiritual avatars and their angels to help rid oppressed and possessed persons, as well as dwellings, of these evil entities.
In this book, angels, demons and Satan will be treated as real, primordial entities separate from the souls of human beings. I do this out of respect for traditional religions, all of which believe in supernatural evil, and also because the weight of the evidence suggests that primordial good and evil spirits are real entities. Some hauntings and possessions are so exceptional that the evil is palpable, and appears to be conquerable only by true angels of God!