If demons existed, they would never 'believe and tremble' because they know about God. (James 2:19)
As the myth goes, demons are just former angels cast out of heaven along with the angel known as, "...the morning star..." (Isaiah 14:12), or Lucifer, son of the morning. This is the only way the story could be written because all of the angels, evil or otherwise, would have come from the Great I AM, or God - the Original Source of Light. And since this Source of Light made everything that exists, seen or unseen, from Itself, then all things, including demons, would also be beings of light.
Because demons would have come from The Light, and exist Within The Light, they would not be evil beings, but beings of love, since The One Source of Light cannot contain anything unlike Itself, and The One Source of Light cannot attack Itself. That means, with all that exists being contained within the One Conscious Field of Energy known as God, there could be no demons ignorant of the fact that they are Beings of God.
And with this knowledge, the demons would know that God is without restriction, without boundaries, indivisible and unconquerable by any other part of Itself. That would be like your left arm turning on your right arm because your left arm hates the right.
But we all know that there is not one part of your body that even understands how to hate another part. It simply works together in perfect harmony. Hence, there really could not be any demons because the current idea of demons contradict everything that the Light is. And there is no part of The Light that understands how to hate a part of Itself.
All of such things are illusions created by our human inability to understand just what Love is.