Reborn as a Background Character, but Bound to a Vicious Female Lead System

Lu Jia was taken to another world by the system after saving a child. [As long as you complete the vicious female supporting role according to the script, you can get a bonus of one billion. The system's judgment is also very simple and crude. She only needs to speak lines in the scene where she should appear to gain viciousness points. The problem is... [Why am I wearing the identity of a passerby? The system is not straightforward and strong. [How can you, a gangster, dress up as an important character? Lu Jia worked conscientiously to complete the task of the vicious female supporting role for the sake of one billion. But the male protagonist is inexplicably cooperative. The original evil female supporting character simply facilitated her. The system looks at the rising points and feels that appreciation is beckoning towards it. Lu Jia looked at the progress value and felt that Billion was waving to her. Although the plot was completed in various ways every time, she always succeeded and retired. Why are all the people around the heroine gathered around her?