Read manhwa Don’t Mess with My Duke Dubless! / Don’t Be My Darling / 내 최애 까지마라

One day, Jade Kinsel finds herself in the world of the novel .She decides that, while she is here, she’d try and change the ending of her favorite character-Duke Dubless. Rather than the sad, underdog second-lead that loses out on the girl and eventually dies alone, Jade would find him his own match and let him meet an ending he truly deserves. She awaits the appearance of Minne, the main character and saintess that will get the ball rolling… But once the original novel begins, Jade notices that something is wrong-the story has changed its course!
https://teenmanhua.com/manga/don-t-mess-with-my-duke-dubless