It looks like the next (current) major Holy War (has in progress for hundreds of years) is between the Sunni and the Shia Muslims. They pull in anyone and everyone along the way that they can. There is Biblical prophesy that can be used to show that Iran will soon burst out and take over much of the Mideast - then will be counter-attacked by Turkey - a replay of old history. As in, history repeats itself. However, this time, it takes on a truly global aspect, since so many world powers have such a vested interest in the Mideast.
These folks know no bounds of brutality. 9/11 was a nice afternoon in the park compared to the evil capacities that these demon-driven people demonstrate on each other on a daily basis.
It is kind of bizarre - the US is playing one side against the other. As in, supporting the Shia (Iraq's majority religion) while opposing Iran (also Shia), but pretending not to notice Iran's military moves against ISIS (Sunni, probably secretly supported by Turkey), while attacking the Sunni ISIS directly who is attacking Assad (Shia-variant) while supporting other Sunni fighters who are attacking Assad. This doesn't even begin to peel back the complexity. I would love to criticize the current administration, but frankly, the situation is beyond comprehension, let alone trying to control the outcome. All this while we are driven by our own interests in the region along with (some) compassion for poor miserable ethnic groups who had no part of this, but are being abused and slaughtered.