From Idler to Tech Tycoon: Earth - Chapter 37: The Day That Started It All.

(The main story has ended!! A 1v1, sweet and clean romance novel) Shen Chuwei suddenly travels back to ancient times to become a neglected concubine of the Crown Prince. She thought it was the beginning of a leisurely life of eating and drinking, but unexpectedly, she ends up being deeply pampered by the aloof Crown Prince.Lady Xu: “Shen Fengyi, you'd better know your place. Tonight is my turn to serve His Highness.”Shen Chuwei says: “The Crown Prince is yours, I promise I'm just here to freeload.”That night, Shen Chuwei was kept in the Crown Prince's room~Lady Chang: “The Crown Princess is mine. You can't even dream of sharing her.”Shen Chuwei replies: “I'm not interested.”Later on, not only does Shen Chuwei become the Crown Princess, but she also gives birth to a pair of twins. The Emperor and Empress are in a scramble to pamper them, guaranteeing a smooth ride to victory.All the women in the East Palace vie to become the Crown Princess through their cunning and devious methods, yet all of these are clearly seen by Xiao Jinyan, who has the ability to read minds, causing him to avoid them.That is, until he sees a small 'salted fish', sweet-talking and soft-bodied, just to his liking, “You will serve me tonight.”As a freeloading 'salted fish', she trembles in fear: “Your Highness, I'm still too young.”

After a shocking reincarnation, our hero opens her eyes to a new (and messy) world the last thing she remembers is reading Lady Viper’s Vow, a dark fantasy novel about a cruel, misunderstood villainess and her path of doom. But when our protagonist finds herself reborn right in the heart of an attack, she’s moments away from a second, way-too-soon death. Just as she’s about to face the end, a mysterious “system” pops up with a single mission: Level Up or Die Trying. It’s bossy, snarky, and her new best friend. As she levels up into a borderline-cheater powerhouse, she discovers her fate isn’t to be a hero, a princess, or even a sorceress, but to protect the one person no one ever expected her to side with: the villainess herself.

A wonder falling down from heaven! A boy possessed by strange blood! Gods tremble! Demons flee! A boy from the land of Dong Zhou. A pink skull as his sworn friend until death. A story of a determined warrior struggling for power. A legend that shakes the galaxy and disturbs the worlds of god, demon and man.

- Description from Novelupdates

Jian Wushuang was reborn in adversity. In order to get his revenge, he began to cultivate Heavenly Creation Skill. With the help of the Heaven defying cultivation method, Jian Wushuang gradually grew into a peerless genius from an ordinary practitioner. With a sword in hand, no one is his match. Using his extraordinary Sword Principle, he killed all his opponents and eventually became number one Sword Master from time immemorial.