I'm Just a Side Character, but I Became the Guardian of the Marquess Family's Heir

I should have perished in the accident, but when I opened my eyes, I found myself transported into the world of my favorite novel. To make matters worse, I was not reborn as a protagonist or a hero—I was merely an insignificant side character. According to the original storyline, the duke and duchess have mysteriously vanished, leaving their estate in chaos, and all the household servants are on the verge of being dismissed. Faced with such a bleak reality, I made a firm decision: I would abandon the plot entirely and live out this new life exactly as I pleased. Or so I thought. My simple plan for freedom is abruptly derailed when I somehow find myself appointed as the guardian of two orphaned twins. This heavy responsibility was never meant to be my role in the story, yet looking at them, I cannot bring myself to simply walk away and leave them behind. With my quiet life now turned upside down, I resolve to take the twins under my wing and embark on a journey alongside them—setting forth into a narrative I was never supposed to lead.