Discussion»Questions»Outside the Mug» If ISIS could blow up, burn to death or behead everybody they thought was infidel would there be less than a billion people left alive?
They do fight amongst themselves.Sunni and Shia Islam are the two major denominations of Islam. The demographic breakdown between the two denominations is difficult to assess and varies by source, but a good approximation is that 85–90% of the world's Muslims are Sunni[1] and 10–15% are Shia,[2][3] with most Shias belonging to the Twelver tradition and the rest divided between many other groups.
ISIS kills Shia Muslims and generally allows Sunni to live. So if the stuck with that throughout there would still be approximately 1.7 billion left.