Seirei Tsukai no Blade Dance - Volume 19, Chapter 10 - The Demon King Is Summoned

Lou Yao Yao wasted her life fighting over a man, only to find out he wasn’t worth it in the end. Because of this man, she accidentally killed her rival in love, and even ruined the man who had always been watching over her.

Getting reborn as her 20 year old self, there is still time to fix everything. Lou Yao Yao decided to live as a genuine vicious woman. After getting her hands on the loyal like-a-dog man, she would show that cheating couple what pure loving affection looked like.

- Description from Novelupdates

Five years ago, she was schemed to have one-night stand with a stranger, resulting in a mysterious pregnancy.Meanwhile, at her engagement party, she was humiliated by her fiancé, abandoned by her family, becoming the most notorious woman in the city.He is the powerful and enigmatic heir to a conglomerate who unexpectedly enters her life.From then on, her stepmother is utterly defeated, her ex-fiancé begs for forgiveness, and her stepsister pleads for mercy repeatedly.He, ruthless as ever, declares domineeringly, “She's mine. Who dares to impose on her?” Everyone is stunned and shocked.Her life undergoes a drastic change.

After forming a blood pact with the Saint and Demon ladies, the good-for-nothing young boy obtained the Yin-Yang divine veins, learned the art of alchemy and martial arts, and dominated the world.The young Shen Xiang had a romantic encounter with a goddess and a witch, and obtained their supreme inheritance, acquired a divine vein that defied the heavens, learned peerless magical skills, and mastered superb alchemy techniques, which made him very successful on the road of martial arts... When he was hungry, he would refine some pills as snacks, when he was lonely, he would flirt with the high and mighty goddess, when he was bored, he would play with those martial arts masters who came to ask for pills, and when he was tired, he would let the delicate wives around him give him massages...