Kasou Ryouiki no Elysion - Volume 2, Epilogue - The End, and The Beginning

A man was transported to Ancient China and eventually became a servant of a declining household without a male heir. He utilized his wits and modern knowledge to help the household and eventually become trapped in the sea of political turmoils of the period.

- Description from Novelupdates

Enemies always meet on a narrow road and when they meet war breaks out.

They met as kids and fought but Zi Han lost.

They met in the army as recruits and even then Zi Han lost.

He lost again as he remained a sergeant while Yi Chen was promoted to the position of Marshal.

Even when his dark history swallowed him whole and shifted allegiance to become the Universe’s most infamous assassin he still lost to Yi Chen.

Zi Han, “Damn it! Why won’t you let me win.”

Yi Chen, “I can let you win in bed if you like?”

Zi Han, “……”

When did enemies graduate from rolling in the dirt fighting to rolling in the sheets….. fighting? That’s the million-dollar question.

.....

She was originally a puppet of her family. Pursued by the police for being a business spy and hitman, she was betrayed and fell into the sea.

When she opened her eyes again, she had turned into an ordinary high school student. Because of a disgraceful birth, she had been crowded out by her relatives. Because of inferiority complex and antisocial behavior, she was bullied by her classmates.

But now she is no longer someone who acts timid. Cheat her, and she will break your bones.

She possesses formidable Jade pupils capable of seeing through walls. Other people have difficulty breaking through jade, their sight for antiques is based on gambles, but she only needs a look.

An undertaking begins as she creates legends in the world of business.

Once upon a time, they laughed at her poor and destitute state. Now looking at her net worth of 10 billion, it can’t be explained.

To the relatives that come to hug her thighs, she must apologize: “We broke off relations long ago, so get lost!”

- Description from Novelupdates

For the wine to be drunk on her wedding night to actually have been a cup of poison and for the one to poison her to be her husband, who would believe it?