Well, certain things in mythos have been known to be demons in disguise of certain things. It may be a shadow man just trying to be extra. Sulfer and other smells of death follow demons. That's their flaw so if you don't smell that then you probably have a fae that's just being annoying.
Tom, Djinn are basically genies. Only they're not the Disney-fied version we've been lead to believe they are. Djinnare derived from Islamic beliefs, though they were not always thought to be strictly so. What you are referring to is simply another term derived from Islamic theology. It states that it is an invisible creature that God created out of ''smokeless fire'' before he created Adam. They resemble humans, in that they need to eat and drink and can also procreate. But they were faster and a lot stronger than humans. However, they will ultimately meet the same fate, as in they will be tried and judged as humans are and either sent to Heaven or Hell.
Demons, especially the higher ranking ones, can "shape-shift" and appear as whatever they choose to. For example, back in 2014, I was visited by the demon named 'Astaroth', and he actually appeared just like an 'angel'. Nothing whatsoever evil or bizarre looking about him. Didn't speak nor act evil either. The only reason I knew it was a demon, was when he told me his name 'Astaroth', I instant!y recognized it from things I've read about in regards to demons.
The one thing they cannot do to their appearances is they are unable to perfectly replicate appearing as a human. There will always be some obvious physical feature which is "off", or flawed in some way. This is what I have heard time and again.
I have a question since you mentioned Islam and Djinn: are certain sects of Islam, like for example Wahabists/Salafists, maybe certain others, considered by most mainstream Shia and Sunni Muslims to be 'Satanic'? I've heard and read that most Muslims denounce groups like ISIL and al-Qaeda as being the "Satanists" of Islam, and both groups happen to be Wahabists/Salafists.
