MTL - For Thousands of Years, My Weakest Brother Has Become a Demon King (1000 Years Later, Even My Weakest Follower Has Become A Demon King) - Chapter 201 "sane" purpose

Yao Mo Xin, the empress of Da Chu died in a cruel way a day after she gave birth at the hands of her husband the emperor, Ye Hong Yi, and her legitimate second sister, Yao Shu Ran. Ye Hong Yi got the throne because of the smartness of Yao Mo Xin, but he hated her because she made him feel like a useless person who needed a woman to become the emperor.

Her soul got in the body of her illegitimate third sister from the same mother Yao Mo Wan. Yao Mo Wan has the mentality of a child because the legitimate wife of her father fed poison to her mother while she was carrying Yao Mo Wan. Yao Mo Xin wants revenge for everything that happened to her, so she seduced the emperor and began her plan of taking everything away from him. She did that while pretending to still have the mentality of a child. She also wants to repay Ye Jun Qing back for everything he did for her while she was Yao Mo Xin. In the process of revenge, she met many people who will fall in love with her wit and intelligence.

- Description from Novelupdates

The Ning family finally found the sole granddaughter after she disappeared for ten years. Grandpa Ning was overjoyed! He embarked on the search for a grandson-in-law in River City. With a raise of her finger, Ning Dai pointed at the Mo family's disfigured Second Young Master, Mo Chen. Everyone thought she was crazy, but only Ning Dai knew that when she was kidnapped, Mo Chen risked everything he had—even with a broken leg and disfigured face—to rescue her from the devil's lair after her elder brother died tragically. Ning Dai returned to repay Mo Chen for saving her life, and also to exact revenge on her uncles for her elder brother's death. Everyone claimed that the Mo family fell from grace after Mo Chen's injuries while Second Young Master Mo Chen became paranoid and ruthless too. No one dared to get close to him. However, Ning Dai insisted on clinging to him. "Second Brother, your medicine won't taste bitter today because I'll give you a kiss to go with it." Mo Chen was about to lose control of his emotions. "Scram. I don't love you." Ning Dai gave him a cheeky smile, "Two kisses, then." Eventually, Mo Chen kissed Ning Dai's forehead shakily, his resolve shattered into a thousand pieces. After seeing how profound Mo Chen's love for her was, Ning Dai was convinced that he would once again stand up for her and stay by her side at the top of the world.