Wearing a camouflage uniform with militia patches and a green headband, Nawar Mohammed is the image of an Iraqi Shiite fighter except for one detail: he is Sunni. Mohammed is one of some 250 Sunni residents of Al-Alam who joined Asaib Ahl al-Haq, an Iranian-backed Shiite militia with a fearsome reputation for kidnappings and killings targeting their community, to battle the Islamic State group after it seized their town.