It makes sense Yang Kai didn't recognise him. Disguises are so ridiculous in this work anyway. Yang Kai sometimes goes undercover, but he always looks exactly the same, just giving another name to people, yet nobody ever recognises him. It's even more stupid than Clark Kent/Superman with the eyeglasses since these folks are supposed to be hundreds or even thousands of years old cultivators, not ordinary mortals. Yet they are all bloody blind.