Fang Yuxin didn't know Zheng Tianhe at all. The reason her complexion drastically changed was that the moment this person appeared, he launched a Spiritual Attack against them!
This was a Spiritual Superpower User!
She suddenly felt extremely grateful that she had let her parents take Bai Qianqian home and hadn't let them come along. Otherwise, the energy fluctuations from the three of them would have definitely not escaped this person's spiritual perception, and Bai Qianqian, who had also awakened a Spiritual Power, would likely have been targeted by him!
Probably because of her cultivation of the Green Wood Technique, coupled with her Soul Power far exceeding that of an ordinary person, she had a certain immunity to any Spiritual Attack and could also identify the type of Spiritual Attack.
