Saint Michael, the archangel of battle, is tattooed across the back of a U.S. army veteran who recently returned to Iraq and joined a Christian militia fighting Islamic State in what he sees as a biblical war between good and evil. Brett, 28, carries the same thumb-worn pocket Bible he did whilst deployed to Iraq in 2006 - a picture of the Virgin Mary tucked inside its pages and his favourite verses highlighted. "It's very different," he said, asked how the experiences compared. "Here I'm fighting for a people and for a faith, and the enemy is much bigger and...