If you were Satan and your goal is to destroy as many lives as you could, what are the two institutions you could attack that would destroy more lives than wars and natural disasters combined? Here's what I would do:

Phase One: If I were Satan, I would capture the medical industry and make it mine. For what other of man's institutions could potentially inflict more harm?

Phase Two: If I were Satan, I would fill pulpits in churches with pastors who teach that God no longer heals the sick like people read about in the Bible. I would have these pastors teach that healing must be instantaneous to be called a miracle.