Greatest Legacy of the Magus Universe - Chapter 43 Apologize

What happens when a fanfic author with a habit of lying and scheming suddenly finds himself as a self insert during Duelist Kingdom? What happens when you have Yugi, Joey, Kaiba, and the rest encounter someone who knows all about every major player in their saga... and sees no problem with abusing said knowledge? Chaos, dear reader. Sweet, sweet chaos

In the chaotic world of Ancient Greece, a modern soul is reborn into the body of a young warrior. Armed with knowledge of future empires, military tactics, and innovations, he has no mercy for his enemies as he sets his sights on dominating the Mediterranean. Ruthless and ambitious, he will use every advantage at his disposal to rise to the top. From the heights of Athens to the streets of Rome, alliances will be forged, rivals crushed, and a new empire built from the ashes of the old. In a chaotic time full of treachery and power struggles, only the strong survive.Dont read yet the novel is a complete mess it will be fixed by the day after tomorow give it a try by then.

“O, Hero!” With that cliched line, Kazuya Souma found himself summoned to another world and his adventure–-did not begin. After he presents his plan to strengthen the country economically and militarily, the king cedes the throne to him and Souma finds himself saddled with ruling the nation! What’s more, he’s betrothed to the king’s daughter now…?! In order to get the country back on its feet, Souma calls the wise, the talented, and the gifted to his side. Five people gather before the newly crowned Souma. Just what are the many talents and abilities they possess…?! What path will his outlook as a realist take Souma and the people of his country down? A revolutionary transferred-to-another-world administrative fantasy series starts here!

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