Yan Taibai did not care much about Wantianming's attitude. As long as Wantianming did not actively provoke him, he couldn't be bothered to deal with him.
If Wantianming insisted on provoking him, however, he wouldn't hold back. That was only out of consideration for Wantianming's sect, the Myriad Magic Sect, having yielded the metal-attribute Spirit Stone mine on Heavenly Gold Star Island.
Otherwise, based purely on that attitude, Yan Taibai wouldn't mind exterminating him after leaving the Heaven-Void Palace.
Chapter 154