Shadow Monarch in DC - Chapter 19: The Secret Shipment.

Jiang Chen, son of the Heavenly Emperor, unexpectedly reincarnated into the body of a despised young noble, thus embarking on the path of the underdog trouncing all commoners. No one has the right to call himself a genius in front of Jiang Chen, as no one has a better understanding of the heavens than the son of the Heavenly Emperor. “Genius? He who adheres to me shall ascend. Those who oppose me can find solace in hell!’

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

The king of assassins was reborn, mastering both alchemy and poison. Sitting inside the space, there was a ghost that loved crying.

Buying a sickly boy for a hundred gold coins, becoming the master of half a country for no reason.

On their wedding night. She slightly hooked her jade finger, “Come here.”

The man tried weakly bargaining, “Can I redeem myself?”

“No!”

“Can we wait for the bridal chamber tomorrow?”

She cast a cold gaze, “Give me a reason.”

“I…..My period is here.”

Her head was covered in black lines, “Do you think you would even believe that!”

After four hours——

She weakly said, “I can’t go on anymore, wait until tomorrow.”

The man revealed an evil charming smile and turned her over before pressing down, “Want to run? Too late!”

- Description from Novelupdates