I don't believe in putting blame for evil in the world on the Devil/Satan is fair. Nor do I believe that all good is down to God. I think the human race should learn to accept that we are of two camps, good and bad. Evil in the world is created by man, and man alone, as is good. Obviously such things as earthquakes and landslides, floods and tornados etc are percieved as evil things too, but this is nature taking it's course. How can these things be blamed on any one person or spiritual being?
Acts of kindness and compassion are performed every day all around the world by Human Beings by their own free will, we just hear more about the evil acts performed by a small minority. I don't need any proof in the existence of a spiritual being, either good or bad, because I know I can be both if I choose to be. At the end of the day, we all know the difference between right and wrong, we just have to make the right choices. I certainly don't blame my mistakes and short-comings on anyone else.