Elseerian (The Chronicles of Lumineia: The Second Draeken War #1)

The assassination of heroes was once a warning--for an invasion that nearly destroyed the world. On the brink of total victory, the black horde mysteriously vanished, leaving terrified survivors...and rumors. As the centuries passed, the holocaust faded into legend, and finally myth. But death is stalking heroes once more, and only a miracle will allow life to survive again..a miracle named Elseerian.