Taking advantage of the sentiments between Dongxi and Nan Bei at this time, and buying their lives, made them serve him. Tang Ye's approach was very astute, avoiding their resistance and disloyalty. Some may call it taking advantage of their weakness. That's somewhat humorous, as it was a matter of mutual need.
Tang Ye gave Dongxi and Nan Bei a new lease on life, allowing them to cherish the sibling bond while alive, which couldn't have been better for them. Otherwise, would they prefer to die together? Death meant having nothing, and after many years, they would just turn into mounds of yellow earth. What use then, speaking of emotions?
Only by living, was anything possible!
When Nan Bei heard Tang Ye say that Dongxi could reach the pinnacle of martial arts even after losing his arm, even stronger than before, she was immensely excited. Ever composed, she looked at Tang Ye with excitement and gratitude. Then she turned to Dongxi, hoping he would agree to Tang Ye's conditions.