The Black Flood — E.A. Rappaport

Demons have breached the void with a plan to claim the world as their own. Can Jarlen discover their weakness before they destroy everything? With dead bodies returning to life and demons roaming the land, Chara and Tyraz wonder what has happened to their friend, Jarlen, the only living necromancer. Not only might he be the one who can return the world to normal, but he might also be the one responsible for the problems.