Why didn't the head of Tianlian Sect kill Chiya?

Apprenticeship is deep. The head of Tianlian Sect and Chiya are the characters in the cartoon assassin Wu Liuqi. According to the plot, Chia was originally a proud disciple of Tianlian Sect and was possessed by desire. When we meet again, there is no pain because of the deep affection between master and apprentice. Assassin Wu Liuqi is a network original animation jointly produced by Aha Entertainment (Shanghai) Co., Ltd. and Guangzhou Xiaofeng Culture Communication Co., Ltd.