Peter V. Brett — The Demon Cycle #3: The Daylight War

Harper Voyager 2013 Paperback 803 Humanity is fighting back. Although the night still belongs to the demons that arise as the sun sets, new wards and weapons are giving those willing to fight in the darkness a chance to retaliate against their core-spawned enemies. But, as humanity is about to learn, not all monsters are confined to the dark. Civil war ravages the north and south, battles fought between those who should be working together. It is up to Arlen -- the Painted Man -- and Jardir -- the self-proclaimed Shar'Dama Ka, the Deliverer -- to put aside their differences and bring their people to terms if they are to have any chance of saving their civilisation from demon-rule. Spine a little curved. Good