What is a Demon?  My opinion is this is a pretty difficult question to answer, particularly because I like to have evaluatable criteria to help answer this typing sort of question.  I prefer to use the golden rule as my criteria. So
  • if an angel is a prezz (short for presence/being) that strives constantly to do unto others as they would have done unto them
  • then a demon is a prezz that strives to get whatever prex (he/she/it ... ) wants regardless of the impacts on others

My experience of demons is that they have become who they are based on their choices and actions.

It may be quite difficult for some to believe that there are prezzes that will strive to make these sorts of demonic choices.  But it is my understanding that it is the nature of this creation to allow for such things in hopes that everyone will eventually learn from the ramifications of their actions.

On Earth, I have definitely met others who consider themselves to be demons.  My understanding was that they consider "goodness" to be weak and overly vulnerable.  These prezzes all seemed to have desires to be in touch with what seemed truly powerful to them.  I have often tried to communicate with Earthers about the potential downsides of such demonic connections.  But they have always seemed terribly self-assured while being blind sided about what sorts of real deteriorations and manipulations are actually occurring.

Pleasure in Other's Suffering?  I think we all do know of instances where some have worked quite hard to selfishly gain from other's suffering.