Your thoughts on "Demonic" beings

I'm very interested in the theme of the book Faust, or any book that has something to do with "selling your soul to the devil"

I do believe to an extent such things exist, but nothing of the sorts have happen to me, so I wouldn't know.

Selling your soul is impossible. The devil himself (Satan) gives less of a fuck about a normal soul. He has billions, if not trillions since humans were made. You can "give" yourself to demons per say. Such as letting them pretty much take your energy or even possession if you let them. But selling your soul to any demon or Satan is quite impossible using the Goetia.