Toaru Majutsu no Index: New Testament - Volume 18, Prologue: Connection Point - Destiny_Joint.

Grandpa Yu often repeated beside the ear of Yu Zhen, saying that he(YZ) has a soul in his body. If he doesn’t properly train in asceticism, and raise then send away the powerful soul, in this lifetime he would have to live as a bachelor. In his next lifetime he would be reborn as a lifestock animal.

Yu Zhen played on his mobile and nodded. On the surface he replied, “Uh-huh”. In his heart he laughed, “hahaha”. Keeping his grandfather in the dark was amusing so the lie was repeated for over ten years without Yu Zhen getting tired of it.

After some years, Grandpa Yu passed away and a cold-faced handsome guy came to his door in a luxury car – with a household register in his hands.

…..

Yu Zhen: The soul in my body reincarnated into someone else’s body to demand repayment, what should I do!

- Description from Novelupdates

Upon waking up, Ruan Xia had transmigrated into a webnovel that she had stayed up all night to finish reading. She had become the villain’s mother.

In the novel, after the death of her first husband, the original owner of the body had hooked up with a Mr. Perfect at the fastest possible speed. Worried and discontent that her son from her first marriage would become a burden on her, she heartlessly abandoned her son.

Having once held the best quality script and informed of future events, Ruan Xia looked at her still alive first husband as well as her future villain son. She sighed. She wanted to apply for a different script!

After being set up and killed by her half-sister whom her ex-boyfriend had cheated with, Mu Siyin woke up one day to discover that not only was she alive, but she had traveled back in time to 2 years before her death.

She became the young mistress of the most powerful family in City T by marrying the young master in place of her sister.

He was cold to her on their first nuptial night. "Just because you played some tricks to get yourself married here, you still mean nothing to me!"

However, she was calm and heartless. "Young Master Mu, don't think too highly of yourself. I despise all that is you — your money and your very being!"

After the wedding, Young Master Mu lived lavishly by spending money like flowing during the day while working his nights away busily. "You said you despised me earlier. Well, which part of me do you despise exactly, hmm?"

Luo Chenxi could not bear the harassment any longer so she tossed out the divorce papers in rage. "I can't live like this much longer..."