Have you ever seen a red-tailed devil? Have you ever seen anything emerge from the ground beneath your feet and begin taunting, tempting, and tormenting you?
Have you ever seen anything or anyone, besides your fellow humans, appear as anything that resembles, in any way whatsoever, an evil entity as depicted in any religious scripture?
I am going to wager - Not. And you know what that means, right? It means that the only devils and demons that exist, do so only in our minds; and are then acted out by us physically based on how we were taught that demons should behave. Every idea that exists of evil and demons has been conjured within the Absolute realm of Spiritual Mind; this is self-evident since thought cannot exist any place else.
As Souls that cohort with a physical brain, we may dream, conjure and bring to life that which we think; but our original Thought cannot exist outside of its original birthplace; in our case, Spiritual Mind. Thoughts are restricted to the realm of their creator and can never become more than the creator allows through Thought.
Consider it this way; since humans were created in a realm of organic physicality, the physical body cannot ever leave this realm. The only way (around) this would be to create an artificial atmosphere that replicates our indigenous environment; such as a spacesuit that holds air to breathe and pressure to hold it all together. Or perhaps a space shuttle, or space station that can support a human structure. But no matter what, our physical body cannot exist in space alone since that is not the realm for which our bodies were made.
Creatures of the oceans obey this same natural law. Fish may not leave the ocean unless they take a part of the ocean with them in some way; for contained within the ocean environment are all the things essential to their ability to live as fish.
Therefore, as with these other creations, Thought too, can only be created, and continue to exist in the realm from which it was conceived. That is, thinking can only operate within a realm that supports thoughts. We will never see a Thought with our physical eyes because eyes and Thoughts were created in different realms. All we can do is (think a Thought), and then translate it outwardly with all the physical elements at our disposal. But our translations will never equal the grandness or complexity of the Thought that sponsored the translation.
Equally speaking, Thoughts of demons, or devils will never exist outside of the Realm of Ideas from which they were devised; in the like, those Thoughts can never be more than the creator of the Thoughts allow, nor will the demonic Ideas be acted out more grandly than they were conceived of in Mind. All one can ever do is interpret the Ideas of how demons are thought to be through their physical body.