Duan Ling Tian's comprehension of the rudimentary form of the Sword Dao was not a secret in the Eastern Ridge Mansion. Many people had seen him using it through Floating Image Pearls when he killed the two intermediate Lords of Gods in the Flying Dragon Sect. This included Wanqi Hong and Wanqi Jue, the Wanqi clan's Golden Seat Elder.
At this time, Duan Ling Tian did not dare to use the Mastery Dao like before when he killed the two intermediate Lords of Gods due to the Emperors of Gods present on the scene. Now that his law of space had improved tremendously, the power from the law of space now was on par with the power from the combination of the law of space and the Mastery Dao in the past.
