I Need Wives For My Gacha System - Chapter 19 --

A girl who calls herself a demon appeared before a timid student named Fumio Kijima. The girl claims to be a campaign girl from the demon world and she gives him the ability to “summon a room” from nothing but thin air.

At first he doesn’t abuse his power and uses it as a convenient ability in his every day life. But one day he is bullied by his classmates under a false pretext and is made to suffer. In the past he would have wallowed in misery and cried himself to sleep, but now he had a power to call upon.

“I will make them regret it!”

Using his powers to summon his “room”, he begins his era of confinement and brainwashing to achieve his goals.

Humanity was on the brink of destruction. Muyoung, an assassin from the Forest of Death, fell to his knees. There were corpses all around him. For years, he had worked for the Forest of Death and had finally been able to eradicate them. Now, he, himself, was about to die. He closed his eyes as he felt his heart stop beating.

She is the slow-witted idiot of the Prime Minister’s Residence. Everyone bullies her. He is the most respected and unfeeling Prince, with frightening ability and absolute envy! Together, they are conferred an imperial edict of marriage.

She acts stupid and tries to decline in every way possible while he despotically escorts her into the wedding…… everyone ridicules the match, but no one knows that the “idiot” has transformed from a loser into a talent.

After the marriage, when they encounter the Empress Dowager examining the room, they act in concert with each other and pretend to be two mandarin ducks deeply in love. Afterwards, she laughs, “The performance has ended. Your highness, please return.”

He laughs softly, “Since you’ve got onto this Prince’s bed, don’t even think of getting off.”

- Description from Novelupdates

This novel is also known as My Apocalypse Domain

On doomsday, Tang Yu unexpectedly got the Lord of the End System, he remained very calm.

Lack of experts? I will construct a pub so I can make ten draws in a row; 　　

Lack of food? I can’t be too cheap with the large pack full of food supplies sent from the market;

Lack of safety? Arrow Tower, Mage Tower Artillery and all kinds of automatic defence buildings. Having many isn’t too many;

Lack of equipment? Workshop production must produce high-quality items. Sir, would you like one? We are having a 20% discount special at nine!

…………　

In short, this is a story of Great Lord Tang building up his territory, attacking some monsters, and ripping off…… Cough, making some money at the same time.

- Description from Novelupdates