Qu Chi's brother is not Zu Er, but another person who also uses the blood knife. He and Qu Chi were lovers, and later he was killed by the magic of a blood knife. When a famous Zu Er got a knife and became angry, Qu Chi tried to dissuade him and fell in love with him later.

Well, Qu Chi didn't know that her brother was dead, thinking that the fire was her brother's, and she didn't know that Zu Er had inherited her brother's mantle. Later, Zu Er took her to see her brother's grave.