The Wyrmling Horde: The Seventh Book of The Runelords

At the end of Worldbinder, Fallion Orden, son of Gaborn, was imprisoned on a strange and fantastic world that he created by combining two alternate realities. It's a world brimming with dark magic, ruled by a creature of unrelenting evil who is gathering monstrous armies from a dozen planets in a bid to conquer the universe.

Only Fallion has the power to mend the worlds, but at the heart of a city that is a vast prison, he lies in shackles. The forces of evil are growing and will soon rage across the heavens. Now, Fallion's allies must risk everything in an attempt to free him from the wyrmling horde.