I Like Darkness

What is it to be a demon? Is it being evil to destroy and conquer all that is good? Is it being powerful and soulless? I don't think so. It could simply be an entity that is called to serve a purpose.....just a purpose. Then discarded, or to be wanted gone and overstay a welcome. To linger where it shouldn't be past it's usefulness....and despised for existence where no longer purposeful.