After Bystander A Ruined the Protagonist Group

In an ABO novel, there is a character known as the scumbag A, whose only role in the story is to occasionally indulge in her scumbag tendencies. In the early stages, she is part of the main characters' play, and in the later stages, she becomes a tool for the protagonist, ultimately meeting a tragic end. Upon realizing she is the scumbag A in the book, Fu Wansen felt a wave of darkness wash over her. If she deviates from the plot, she will be erased by the world. To survive, she must diligently play the role of the scumbag A. It is said that the protagonist O is a wealthy illegitimate Omega who pretends to be an Alpha, tasked with competing for the position of heir against her half-brothe...