Socially Awkward, but the F4's Sister-in-Law

Muse transmigrated into an alternate-universe aristocratic school novel. The good news: she wasn't caught up in the love-hate drama between the school's F4 and Cinderella. She was just a random passerby. The bad news: she had only one day left to live. To extend her lifespan, she had to complete friendship quests assigned by her bound System. The even worse news: she was socially terrified! The severely socially anxious 520 System was quite enthusiastic. "Sweetie, if you can't take the first step, I can suggest some sunny, cheerful, sincere, and kind classmates as potential friends, and offer you some tips on how to befriend them!" But the first step Muse couldn't bring herself to take was leaving the house and facing other people. One day, when she was forced to go out again, she saw a handsome, six-foot-three buzz-cut guy holding a cat beside a trash can. His arm muscles bulged dramatically, his fierce glare could make a child cry, and there was a streak of blood on his cheek. "You..." Muse's body stiffened. Her knees buckled, and she instinctively bent down to support herself. In the end, she crouched in front of the buzz-cut guy and bowed. The buzz-cut guy: ? Muse: "I..." Her mind went blank. Facing death without flinching, she recited what the System had taught her: "I want... to be... friends with you!" The cat broke free, stepped on her head, and meowed haughtily. The buzz-cut guy's low voice fell into her ear. "Sure." "...H-how do we do that?" "Just give me your household registration booklet." Why did she feel like she'd been conned... * After all sorts of twists and turns, the System's evaluation was that Muse still hadn't managed to befriend any of her targets. Muse: I think I'm done for... Then F1 stepped in front of her with an air of defiance, leading F2, F3, F4, and the rest of his lackeys. In an incredibly cool and domineering fashion, they all... bowed. They bowed...? "Welcome back, Sister-in-Law!" "Anyone who dares bully our Sister-in-Law is the lifelong enemy of all four of us!" Muse slowly typed an exclamation mark. ...Did she have four friends now?! * Shi Cun, eighteen years old, had been fighting for fifteen years. His exploits were enough to make children cry, and everyone who saw him trembled and called him Big Brother, including his love-struck younger brother and that brother's good-for-nothing friends. One day, he decided to turn over a new leaf. His old man, who was only two years away from middle age, demanded that he clean up the family business as soon as possible and find a respectable girl from a good family to marry, to balance out the family's shady genes. His dad: "I didn't have a choice back then, but you do! If you don't get married, don't come back to this house!" Shi Cun coldly took the only cat with him. The cat latched onto a quiet, gentle girl who looked sweet and innocent, yet had the courage to confess to him. Shi Cun, who really wanted to fall in love but had absolutely no luck with women: ...She's so cute. I want to marry her. [Smitten.jpg] When his dad asked him about her, Shi Cun said, "She's a good girl." "The cat picked her." *The cat walked across the keyboard *The cat picked the male lead *Cat: Meow meow meow (It's an alternate universe, people can marry at eighteen) Theme: Have the courage to take the first step toward communicating