For religious stuffs , human beings are perfectly talented to use their imagination properly. For that reason, Ancient people created all the religious beliefs wit their beautiful mindset or else there is no holly stuff like god , angels etc. in reality. For second question, People have tendency to be an evil one. Some people can easily suppress those evil feelings but others cannot. Due to this, there is horrible stuff called terrorism on earth. For the last question , of course there are horrible powers to control ongoing evil stuff on earth.