MTL - Peerless Demonic Lord - v19 Chapter 2067 I think of you.

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

After 2000 years has passed, the ruthless demon lord has just been reincarnated! But his aptitude at an academy for nurturing candidates for demon lords is, “Inept”!?

Having the capability to destroy humans, elementals, and gods, after a long period of countless wars and strife, Arnos the demon lord became sick and tired of all that and longed for a peaceful world, so he decided to reincarnate to the future.

However, what awaited him after his reincarnation is a world too used to peace that his descendants became too weak due to a huge weakening in magical powers.

Arnos enrolled in the Maou Academy established to find any students that might be the demon lord’s reincarnation, but his powers are too extraordinary that those in the academy couldn’t properly judge his powers, so he’s regarded as an “Inept student”. Being underestimated and avoided by most people there, he recruited a girl friendly to him, Misha, as his subordinate and comrade, and strives to climb to the top of the demon race hierarchy to one day reclaim his former title and status.

Su Bai wakes up and finds that the world has changed drastically. He realizes he has come to a world of pets. After accepting the new setting, he is determined to become a powerful Pet Tamer.

On the wedding night, she was tied to his bed.