Elite Mages' Academy - Chapter 655 - Martin’s Potion

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

Reborn into the world of Yugioh, it's natural if my goal is to become the best duelist!

After making preparations for transmigration into the VR world “Mystical Era”, the previous veteran player Xia Yuan becomes an NPC, and is even made the fourth son of the Duke of the Empire!Already prepared for a boring aristocratic life, he never expects that the era has totally changed!As the last obstacle, his family has been labelled as a villain by the new aristocracy and will soon be crushed by history! Xia Yuan has no choice but to gradually strengthen his own power according to his knowledge of the game's history.Lost treasures, forbidden ancient weapons, secrets of immortality, forgotten epics...With one's own strength, save the world! Change fate! Rise from the ashes!...The knight swears, the mage sings, and the dragon spreads its wings!Pursue magic and truth, and control the fate of yourself and the era!Stand in the clouds, above the floating city and the throne of the sky!The bell rings, and the signs finally appeared.-It’s time for the stars to align-

In a world where its inhabitants can destroy a city wall single-handedly, the empress has a kirin as her pet, and the imperial palace of Great Xia has a pool containing a dragon. There is also a Sword Mountain where spirit swords occasionally leave in search of a master .