Ankoku Kishi Monogatari ~Yuusha wo Taosu Tameni Maou ni Shoukansaremashita~ - Chapter 161.1: Changeling

A car accident causes Yan Chuang to traverse into a martial arts world resembling ancient times, bringing along a 'Purple Mist Palace'.Teaching by Example (Level 1): Your explanations will increase listeners' comprehension efficiency by 50%, and their understanding and thoughts will feed back to you, granting you corresponding 'insights'.The Great Dao Cushions (Level 1): The Purple Mist Palace contains six Great Dao cushions that aid listeners in better understanding explanations and grasping the Great Dao. The effect of 'Teaching by Example' is increased by 1000%. Note: Only two of the six seats can be changed once.Treasure Nurturing Rock (Level 1): You can use 'spirituality' to enhance and nurture items.Method Development (Level 1): You can set up research tasks, gain inspiration, develop martial arts, and complete tasks to gain 'insights' and 'spirituality'. Currently, you can create 2 tasks.Upon reaching the other shore, Yan Chuang laughed and said, “I didn't specifically study martial arts, those were merely insights gained while preaching to disciples.”

Legend says, that there is a great demon, who is the human kind’s public enemy. He is the galaxy federations’ nightmare as he wanted to conquer the whole universe. On the first day, he completely took out the human fleet, plunging them into disorder. On the second day, he declared that he will wipe out the whole federation. On the third day, he declared——that the hero who shot him in their previous battle must marry him, or else, he will destroy everything.

The galaxy federation president and the council members had a long meeting after that. They decided to dispatch a soldier, Wu Xing Yun, and marries him off to the arrogant demon. Wu Xing Yun was once a hero who fought for the nebula, and henceforth, he was tasked—— for the sake human race and the universe’s peace, to eliminate mistresses, settle his matters with the mother-in-law, and fix the man’s crooked ways.

Wu Xing Yun was very perplexed when he asked his commanding officer: “Sir, why did it have to be this way?”

Commanding Officer: “Soldier, bear in mind, that this mission of yours, is for the sake of the universe and mankind’s happiness. You must hold on to your husband, and fight other mistresses! Do you have the confidence to accomplish this task?”

Wu Xing Yun, stood straight, saluted, and instinctively replied: “Sir, yes sir! I will accomplish this task!”

- Description from Novelupdates

Revenge is a dish best served cold, with dollop of whipped suffering and a sauce of acute humiliation.Karma would do anything to exact revenge on the one who was responsible for her mother's death, her father's disdain and distrust, and a miserable life.She was manipulated, maltreated, and humiliated by the one she trusted the most. Her stepsister!!Discovering she had only three days left to live, Karma would go to any length to exact revenge. Even offering herself to the scary and powerful demon overlord.A contract. Blood oath. Manipulation. Betrayal. And lots and lots of revenge.