Demons are pure spirit, that is they have no actual physical body. However, as with angels and other assorted spirit beings, they are powerful enough that most can take a physical form if they desire. And not all demons are evil, some can actually be quite helpful I've been told, but still extra care is to be taken in dealings with them, as they can be wily and often have a hidden agenda far beyond your own intentions....
It depends what view you wanna take. I believe demons and angels are both very powerful beings. Some people believe demons are good, but some believe they are bad. Since I am Christian spiritual, yes I do believe in demons. I have felt demonic presences before.. they're not nice lol.. Demons, like said above, are pure spirit, like angelic beings, but opposite sides of the spectrum. There are higher levels, and lower levels spirits vibrate too. From what I know, I think, demons vibrate at a lower level, while angels vibrate at a higher level. Angels are pure light. Light shines in the darkness.
Hope this helps x
of course the demons are real, and they have differents levels of status and power, someones have a low level and little power but others are very powerful.
they are spirits in astral energy but a lot of them have the power to appears with a physical form in certains circunstances, like when you perform a evokation,they can appears like a person.
but be carefull most of them are very dangerous, maschevous, really bad, the energy of them is very negative and have a fierce hearts, some really experts can work with them.