This is Akumagi the Apex Dragon of Darkness originating from the Dragon's World multiverse. He was sealed away by the Apex Dragon of Light in an act of jealousy and now seeks first his unsealment and second his revenge. The one you see in the picture is his sealed form at small twisted fraction of his full body. Akumagi's sealed form measures in at 154 meters/505 feet long, 65 meters/213 feet tall, and weights 7,865 kilograms/17,339 pounds.