GB: The Useless Bystander System Helps Me Enjoy Retirement

[Gender-bender, female lead × male characters + no fixed pairing + seemingly gentle, secretly unhinged heroine + giving up] First world: The real and fake generals vs. the young woman who claims to be a fiancée. A nobody courier caught in the wars between feuding lords (beginner's training world) Second world: A lecherous sister-in-law nobody vs. her widowed brother-in-law vs. his young male companion brought as part of his dowry vs. a famous courtesan... (I can't remember...) A nobody's aunt has improper intentions (female-dominated world; the terminology might not be quite right) Third world: A melodramatic tragedy full of crazy men and women (a casual piece; the author's mental state is just lovely~), no pairing Fourth world: White Tiger beast-king heroine vs. the lucky guy who gets a young husband The state assigned me a husband. Fifth world: A rebellious crown prince disguised as a man vs. a gentle genius tutor Sixth world: A priest disguised as a man vs. a demon who deliberately tempts him vs. an angel on the verge of falling System 05: Congratulations, Host. You've been bound to the Nobody System. Yi Ran: Why bind me? System 05: Because you're ordinary enough, Host. Your life follows much the same path as most people's, and is even more bland and boring. You're a perfect fit for the role of a nobody. Yi Ran: ?!! Are you sure that's the life you're talking about?! The heroine's early characterization is a disguise. She's been acting all along: peel away one layer and there's another beneath it. Put simply, she has countless masks stacked on her face.