Passing Through a Passerby, I Rely on Me to Save the World

[No male protagonist + big female protagonist + behind-the-scenes + fantasy] also known as [Surprise! I'm just an ordinary girl] When all the villain's plans failed, he was walking on the street and a girl passed by him. He had a strange premonition and stretched out his hand to stop her and asked: "Hello, do we know each other?" The red-haired girl carrying the violin turned her head, took the lollipop in her mouth, and said with a smile: "This is the first time we meet, my name is Lin Xi, but we can get acquainted." Lin Xi accidentally traveled into a "Forbidden" novel and became a passerby with no sense of existence. The world is facing the invasion of alien beasts, and there are evil gods manipulating the situation behind the scenes. Humanity is in an unprecedented crisis. As the behind-the-scenes guardian of the protagonist group, Lin Xi must silently help them grow and fight against powerful enemies without revealing their identity. She uses her wisdom and the abilities given by the system to secretly decipher the enemy's plot, create powerful props, and provide key intelligence. However, with the invasion of unknown forces, Lin Xi's actions gradually attracted the attention of the villains. She must protect the protagonist group while hiding her identity to avoid being discovered by the villains. In this war that concerns the survival of the world, how will Lin Xi silently protect the world as a passerby? Can her existence change the final outcome?