There was no lack of means to hide one's strength in the cultivation world. Some were very simple and could be easily seen through with a little attention, but some could be hidden very well, almost invulnerable.
If a high-level master deliberately hid his strength, it would not be difficult for people stronger than him to see through him. But if his strength was lower than his, it would be very difficult.
According to Nantian gate's judgment, since the other party was able to kill Nan tianyong, then he should at least be in the late stage of the foundation building realm, or even higher. With Yu Zhe's mid stage of the foundation building realm, it was normal for him not to see through the other party's disguise.
