I've Become the King of Villains in the Game - Chapter 32: Iron Fist Strike

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.

***

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

“Martial Arts World...” Death murmured, shocked by the turn of the events. How could he, primordial being of the afterlife, get tricked by a mere human? Not just a mere human, but also earthling, race that was weakest of the twenty realms. Death realized the extent of his mistake. An earthling had just jumped into the river of the reincarnation, where he definitely didn’t belong. It was too late. The damage has been done. The matter was now out of his hands. “Kiernan Hunter...” ... Remake of the Martial Arts System, and while the concept stays the same, the story is completely different. A few names, etc, stays the same, but mostly whole new story.

The main character is reborn as a character from a game he played in his previous life. This character falls into ruin along with the villainess, spending the last of their years together. A man named Kururi Helan.