The Signet of Heavenly Dao

The two jade carvings were all red as though there was blazing flame inside, and yet, they were also lifelike, like two living creatures. However, there was a slightly invisible grey imprint on each head of the two jade carvings. Fortunately, Tang Xiu had sharp eyes and he could catch it. He wouldn't have been able to do so with the naked eye if he were an average person.