From the Void — Bryan Smith

The wall separating earth and an alternate reality has crumbled. Soon an army of winged creatures has torn its way into our world, laying waste to the entire planet. But this is only the beginning of the human race's nightmare. A strange rot begins to infect our world, causing inorganic matter to decay at an accelerated rate. Gleaming modern skyscrapers fall to ruin in a matter of weeks. Cars become rusted hulks. Two other creatures from the alien realm, each far more powerful than the winged warriors who decimated the planet, have also slipped into our world. One exists only to kill and destroy. The other is its ancient enemy and has come to earth in a final attempt to vanquish The Dark One. Some of the surviving humans find themselves used as helpless puppets by the opposing forces. They are pawns in a larger game destined to end in a final showdown that will determine the ultimate fate of the world. From the Void was originally published as Darkened.