1x51 - Blue Dragon

The final battle arrives between Shu and the more powerful demon Zola. After Shu defeats Zola everyone begins the resealing of the darkness. But they learn that in order to free the world of darkness, a sacrifice of the shadows must be made. So everybody uses up every last drop of energy that their shadows possess and they reseal the darkness. The world returns to normal, and everyone resumes their normal lives.