Storm Dragon The Draconic Prophecies, Book 1

A war hero, his mind broken by the wonders he witnessed on his last mission for his nation, has spent years in the deepest, darkest prison in all the world. Wallowing in despair and ever on the verge of madness, he is caught by surprise when a band of strangers breaks him out. But his rescuers don't exactly have his best interests at heart. The magic relic that broke his once-brilliant mind may be the key to stopping worldwide destruction-and whether he lives or dies really doesn't concern them.