if I remember right, the "uncle" is the guy from early chapters of the comic. He's not blood related with her and "uncle" is just something she calls him.
@AbyssalMonkey Yeah web comic cuts alot of the stuff that explains. She set up a barrier and had Leng Shuang standing guard. Which she believed no one would be able to enter the hot springs, so that was supposed to show how skilled or powerful he was that he got in without being stopped. Also he entered the hot springs to hide, he didn't realize someone was there.
Later on in this ark you will find out why he is in Green Gallop Country and why he was in the Green Gallop Country's Black Market.
I feel like I also need to point out "Uncle" isn't family Uncle term but Martial Uncle term. He is the guy she met when she was disguised as a beggar and who she followed into the woods with at the beginning of the series.
Everyone: We must get the Ghost Doctor to help fix her face
The Ghost Doctor, eventually, I assume: Uh, I was already planning to fix my face. Thanks for asking I guess?
Oh, it's handsome uncle! He's in my strike zone, but didn't that early comic imply that he's actually the white-haired-pretty-boy/god/maybe-transported-her-to-this-world-masked-assassin?
That makes him too young (looking) for this cougar, oh well.