Actually, the answer is very simple.
Not to mention that Cang Huaimie is from the Undying Heavenly Palace, nor the conflict between Ye Xuan and the Undying Heavenly Lord. Just for the sake of not exposing his identity, Ye Xuan must kill Cang Huaimie and Chi Yan Daoist today.
The reason is simple.
Cang Huaimie has already noticed him. Although the opponent hasn't remembered who he is now, if Cang Huaimie leaves, he will definitely investigate Ye Xuan's identity.
Once Cang Huaimie thinks carefully, he will definitely remember who Ye Xuan is.
By that time, it won't just be Chi Yan Daoist. Cang Huaimie will undoubtedly relay his information back to the Undying Heavenly Palace, and even the Undying Heavenly Lord might personally come to kill him.
So, when Ye Xuan saw Cang Huaimie and Chi Yan Daoist, he had to use any means to keep them there, absolutely impossible to let them leave alive.
