The Crystal is a sphere made of Crystalic Protodermis. It is the power source for The Fang. It has a special power that alowes any being to put his or her life force into the Crystal, so that he or she can not be killed unles the Crystal is destroyed. Also, if a being puts his life force into the Crystal, anyone who he considers his team will be invinceble also, i.e: If the leader of a Toa team puts his life force into the Crystal, the entire team will benefit. Same for the captain of a ship. He and all whom he consideres 'crew' will be incapable of dying. Also, if it is contained in a building, or even a ship, as long as The Crystal is surounded by four walls, what ever it is in will also be incapable of being destroyed.