>>> Don’t forget too that demons can appear as creatures of light.
Not quite. Satan himself can appear as a creature of light.
Satan is a fallen angel... not a demon... there’s a difference.
All demons are fallen angels. Satan was an archangel, like Gabriel and Michael, so he was cream of the crop, but no, demons are corrupted angels, not a separate creation.
Actually Satan means accuser whereas Lucifer means morning light or star. They may be different. I don’t know the exact nature of this accuser. If you know something different that you can cite, please let me know.