NAEL MARCUS NISSAN sat smoking with his legs spread on a burgundy couch in an abandoned home in the village of Baqofa, 15 miles from the Islamic State front lines. Nissan was a fighter with the Dwekh Nawsha, one of the three primary Assyrian Christian militias founded in the Nineveh Plains in northwest Iraq’s Kurdistan, in the months after the ISIS invasion in June 2014. The Dwekh patrolled Baqofa in a black pickup truck with a small crucifix scratched on its side and a Russian machine gun mounted in the bed. They spoke Aramaic, the ancient language of Christ. Nissan was 25 years old, with high cheekbones and a trimmed goatee. He wore aviator sunglasses, a floppy camouflage hat, baggy fatigues, and an ammunition vest stocked with grenades and cigarettes. He preached gospel at the evangelical church in Dohuk, and since he learned English from listening to ’90s-era rap, he quoted Scripture in the cadence of Ja Rule. “I’m from New York,” he sang. “No, I’m from Baghdad!” His favorite song was Coolio’s “Gangsta’s Paradise.”