MTL - The Roots of Manga - v3 Chapter 294 give it to me

In a morgue filled with the bodies of Uchiha clan members, he opened his eyes...A mysterious voice echoed in his ears...With a bewildered expression, he muttered, “Save the Shinobi world? What does that have to do with me, a mere Uchiha survivor?”

Arren was reincarnated as an extra in the book world. However, unlike the others, Arren was determined to play his role well and be the best extra ever.He was successful until that one unfortunate night that would make his second life an unpredictable one. He also began to doubt that perhaps... He wasn't the useless extra he always thought he was.R18.OMEGAVERSE/ BL

[Complete 1V1 Pure Romance] Zhong Xiaoxiao had transmigrated. When she opened her eyes, she found herself on her wedding night, “You might as well prepare to be a widow.”Before she could understand what was happening, her cheap husband had fled, and she became the vilified and reluctantly married country bride. Life is like a dream, but one must carry on. So what if her reputation was in tatters? Rolling up her sleeves, she set to work with her whole family. When they met again, even if they couldn't get a divorce, acting as a fake married couple was still an option, right? However, as she continued to pretend, she actually fell... [New recommendation “Reborn Husband Tender Wife”]

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