One Piece - I Am A Different Luffy! - Chapter 440 - 439 - Departing for War 02.

Su Ran, a music prodigy, woke up transmigrated into a book.

At that point in time, the main story arc in the book had already been completed. As a villainess female supporting character, not only did she need to take over the original owner’s pitiful life in poverty, she also gained an instant son right at his rebellious period.

Ten or so more years from then, the son would turn into a twisted, evil villain. He would appear in one of the extra chapters to pick on the male and female lead’s children.

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Su Ran: Son, you shouldn’t be too outstanding.
Su Han: Why not?
Su Ran: ’cause you will be killed.

Su Ran: Son, would you like to learn music from me and become a zen, little fairy boy who only needs to drink dew.
Su Han: No, I want to go into business so I can support you.

- Description from Novelupdates

During the Yongle period of the Ming Dynasty.

Zhang Anshi was ignorant, and he committed a heinous crime.

His brother-in-law is the prince? Oh, that’s all right!

- Description from novelbuddy

Six years ago, he disappeared silently! After six years, he becomes the unparalleled "God of War" and returns with glory, only to find that he has a daughter whom he never knew of. Looking at his wife and his daughter, he says, "In this lifetime, I'll bring you the greatest honor and glory!”

Wealthy, powerful and handsome; Gu Jingze is the cream of the crop in the entire country. Every guy wants to be him and every girl wants to be with him. His life is perfect… except that he has one tiny secret that keeps him from getting close to any woman—apparent impotency.

That is, until he wakes up in bed with a total stranger one day. The next thing he knows, he is forced to marry this stranger; a feisty and boisterous woman by the name of Lin Che.

Lin Che is an average girl whose only aim is to become a successful actress. Ostracized by her family and forced to become independent, she cooks up a scheme to attain her goal. But her plan fails and she ends up marrying this cold and seemingly heartless Gu Jingze. Not only that, she must now find her place in high society, where jealous women and devious plots lay abound – all while juggling her new career.

Two strangers under one roof: From the outset, they agree to stay out of each other’s lives, but he somehow always manages to appear during her moments of crisis. Slowly and unwittingly, Lin Che begins to find it difficult to imagine a future without him. Will their relationship grow, or is their marriage destined to remain just a contract?

- Description from Novelupdates