Lu weiyang is the emperor of a vast and powerful empire, the emperor weiyang bought a violet sapphire ring from a secret auction for a very expensive price exceeding the treasuries of entire kingdoms. Whoever wears this ring becomes the owner of a very powerful monster and its Guest. Guest cannot directly harm their owner, and can’t escape from them, because the ring's owner can torment the monster by pressing the ruby ​​on the ring. Guest will feel pain in their veins as if fire were coursing through their blood. But the ring doesn't just restrain the monster if the monster dies, the ring's owner dies too.