Tarkin had ascended to Godhood and became powerless to stop what he wished he could. So he built and island and called it Terramore. He then put a thought in the mind of anyone he thought who could survive the test, and stop the war. That was five hundred years ago. You are now his last hope, if you fail it is predicted that the world will fall into a uncontrollable chaotic downfall in which everything will be purged from the world.