Synopsis

A web novel author is suddenly reincarnated into the world of his oldest novel as an extra whom he doomed to a miserable end.
To escape this fate, she decides to use her knowledge of the novel and her skills as a Prophetess on behalf of the Duke of the North, another extra who was only mentioned in a few lines and who died "heroically" against a Dragon to mark the beginning in the era of her son, the protagonist.
With his modern knowledge and skills, he prevents the tragic fate of the Duke and his lands, takes care of the Duke's children, as well as bringing never-before-seen prosperity to the commoners while helping to get rid of the greedy nobles who tormented them. . . .
However, perhaps he overdid it, as it all backfired on him in some strange way.
"Duke, I have to return to my town..."
"I'm sorry, I can't allow it."
"...Can you tell me why?"
The handsome duke gave her a cheeky smile that made her want to punch him in the face.
"Because my children like it a lot, that's why"