Bai Wuxiang's human face disease was different from Xie Lian's.
The Calamity's curse was a disease and had these qualities:
- Infects the body.
- Not always deadly.
- People who have killed are immune.
- Target: anyone else.
Xie Lian's curse was a weapon and had these qualities:
- Eats the body.
- Deadly.
- People who have killed can be affected (the target was Lang Ying, then Xie Lian himself, ultimately taken by Wu Ming).
- Target: anyone.
It would all have been easier for Xie Lian if his original target was available. He wanted to kill Lang Ying, not the common people, that is why BWX's plan went shit.
Because his original revenge plan was ruined, he got insecurities about his "evil path" and tried to convince himself that commoners were a good next target... which was not.
I wrote a short story based on this analysis. "The night of the beautiful crime."
