Sir, How About A Marriage? - Chapter 886

He—an enigmatic and cold-blooded soldier with a mysterious background.
She—a ruthless and bloodthirsty spy.

Xia Lian, a 21st century military doctor died in an explosion and found herself transmigrated to the body a 12 year girl. Her mother died and her father abandoned her and her little brother for another woman.

Freshman student Yang Dingtian possesses the Nine Yang Body, found only 1 in million. His Yang Fire is incomparably vigorous and thus, he cannot be near a female’s charms for his entire life. On the night of his 19th birthday, he decided to bid farewell to his virgin life. After stealing and tasting the forbidden fruit, he spontaneously combusted as the result!

In death he crossed over to another world; a world that held respect for Martial Power. His, originally, catastrophic Nine Yang Body was the Nine Yang Body that couldn’t be seen in a millennium! He was saved by a mysterious old man when he was at his last moments and the old man received him for a disciple, then betrothed his daughter to him. Thus, in this odd way, Yang Dingtian became the successor of the largest clan under Heaven, and became the number-one-beauty-under-heaven’s fiance.

- Description from Novelupdates

____this story sets in Japan that developed a little different history from yours.

This is how a Japanese Princess relieves her stress of the day by using the latest VRMMORPG, and while playing the villain there, the first town turns into whirlpool of chaos, smashed the underground organization in one hand and went for a coup. It’s literally a playtime diary of a girl who is called as “Genocider-san”, “Roaming Last Boss”, “A different person plays the game”, “Raid Boss”, “Ruthless”, “Calamity”, and such by the players.