Tang Wuyan is a killer and Yue Qi is a guard.
Tang Wuyan was responsible for killing people and setting fires, while Yue Qi was responsible for protecting the young master.
Yue Qi is a cute fan, I've been looking for Yue Qi's articles but couldn't find any, so I had to write them myself. The writing is poor.
PS: The heroine kills people like crazy, but she has a conscience and won't meddle in other people's business.