The Elite Assassin Becomes a Flat and Ugly Nerd! - Chapter 816 - : Emergency

In an inaccessible village, there were a few houses on the hillside.

People from far away were attracted here and the mountain road was crowded with luxury cars, because, in this town, there was a young man with incredible medical skills who could cure all kinds of illnesses!

- Description from Novelupdates

The world was once at war with 10 alternate worlds. This was known as the Concept War and our world won 60 years ago. All of this was concealed so no normal people are aware of this fact in the current time.

After the death of his grandfather, the high-school student Sayama Mikoto is suddenly summoned by the giant corporation IAI. He learns this world is headed for destruction due to the acceleration of the Minus Concepts. To prevent this, negotiations must be undertaken with the survivors of the other parallel worlds so their 10 concepts can be released.

And so Sayama is caught up in the final battle to clean up after the Concept War which left behind so much enmity.

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

Yeho is a distant relative to a king in a small kingdom. Even though he is a distant relative, his house was very poor, and his mother was addicted to gambling. One day North Empire asked for Princess Sooyoung to be a concubine of an old Emperor because she was known for her beauty. But the king really loved his daughter so instead he ordered Yeho’s older sister to disguise as Princess Sooyoung and marry the old Emperor.

Yeho told his sister to run away with her lover, and his sister had to leave her younger brother alone with his mother. After she ran away, Yeho asked his mother to give the things back to the king that she got for trying to sell her daughter, but his mother already used the gifts to pay off her gambling debt. He was trying to give the gifts back to the king to take away his order, but now he can’t do that anymore. He tells his mother to run away, and he disguises as his sister to go to North Empire.

After he got there, he was trying to tell the Emperor the truth and take away his life, but the Emperor went out for few days to look around his empire. When the emperor came back, he wasn’t as old as he thought.