Resurgence of Ancient Darkness

When Shadow's team healed reality by closing the last tear, they paved the way for a new evil, one that has been patiently waiting for its chance to rise again. Shadow must build a navy out of his fledgling Battle Wizards and carry the fight to the enemy before it comes for them. Meanwhile, the old man and his steel-eyed partner are making their own plans, and the peace that once reigned throughout the galaxy has come tumbling down.

The Lost Tales of Power is an open-ended series of sci-fi/fantasy books set in a vast multiverse. Resurgence of Ancient Darkness is the fourth book set in the Lost Tales universe.