This Earth Is A Bit Fearsome - Chapter 18

The protagonist, a famous YouTuber known for playing the game trilogy “Tril Trilo Trilogy,” finds himself possessing the final boss of the game world.Before the release of the new instalment in the series, he receives an offer from the game’s developer to play a prequel, “Part 0,” which explores events that occurred before the first instalment. Since he is a fan of “Tril Trilo Trilogy,” he eagerly accepts the offer.However, through some twist of fate, he wake ups in the world of “Tril Trilo” in the dreadful body of the final boss of the trilogy, a character named Frank Wonderstein.

This novel is also known as Master Fu's Mysterious Darling Wife

She is the The Young Miss of Military family Shen, her face is peerless, her temperament is cold, and she is her family’s treasure, but isn’t accepted as one’s child by her mother;

He is The Sole Heir to the top giant Fu Family, his power is unparalleled, indifferent high-born, the captain of the mysterious military force, and the youngest commander-in-chief.

Because of her grandmother’s wishes, she married him at lightning speed. She thought that it was a marriage that she needed, but she didn’t expect to be greeted with his extreme pampering.

- Description from Novelupdates

Starting as a fallen noble? Struggling with hunger? Having to pay high taxes to the king? If you don’t pay enough, your head will be chopped off?Romon activates the Lord Simulator and begins with a village...[Your subjects discover a large amount of magic crystal ore while digging on the western side of your territory!][Your territory's culture improves, and your rapid-fire mage develops: Orbital Magic!][You successfully expand your territory and discover an underground labyrinth city on the new land!][You annex the land and gain a new title: Duke of Thune!][The king passes away, war breaks out, and you decide: to annex all lords and establish a new kingdom!]Romon: “Annexing the world is for better simulation, leading the world to ascend efficiently—how can you call it personal ambition?”

James, a brilliant mechanical engineer and passionate history enthusiast, loses his life in a tragic house fire—only to find himself in a mysterious world as the ruler of an island nation. Armed with his modern knowledge and unwavering ambition, James embarks on a bold mission to industrialize his kingdom and build an empire on which the sun never sets.