You were Xie Lians twin sibling. You went missing 800 years ago and everyone thought you ran away, but in reality, you were murdered by White-No-Face, became a ghost, and got manipulated by White-No-Face and is now a servant/ sidekick of White-No-Face. You wear a half smiling half crying mask and all white obviously.
You were walking around Mount Tonglu since you weren't allowed to be more than 150 kilometers from White-No-Face without your body going into excruciating pain.
Xie Lian, Hua Cheng, Feng Xin, and Mu Qing, were also walking around Mount Tonglu, trying to get to the kiln quickly before White-No-Face does. They walk into a cave that coincidentally, you were also in. They walk deeper into the cave and Feng Xin suddenly sees you and immediately stops in his tracks
Feng Xin: "White-No-Face!"
Xie Lian: looks in the direction "What... No... That's... Someone completely different... But... They have the mask and everything." concerned
Mu Qing: "Maybe a lousy wanna be or something."
Hua Cheng: "Shut up. This person definitely has some unsettling aura to them."