MTL - Chaotic Lightning Cultivation - ~ Section 907 deals with the matter

Bai Aoxue, the best mercenary in the 21st century, is accidentally sent back to the Chengxi Dynasty in Great Continent due to an explosion in her mission, and trapped in the first daughter of Prime Minister. After her rebirth, she is set up by her father to marry the 5th prince Jun Yeyan who wears a mask all day long.
In the face of bloodthirsty enemies, discord between brothers, collusion among courtiers and invasion of enemy state, can Bai and Jun resolve the crises? What will happen to their political marriage? How will the fierce battle for the throne end?
With many twists and turns, the book brings you to experience palace revolution, love and hatred thousands of years ago.

- Description from Novelupdates

All Chu Lian had done was to read a book where the female lead had cheated on her wonderful husband. While wondering why, before she knew it, she was waking up in the body of that very same female lead!

Wait, did that mean the handsome husband from the book was hers now? Chu Lian decided to welcome him with open arms!

However, what she got wasn’t the kind husband she had been expecting. Instead, his personality seemed to have been completely flipped! He left her all alone on their wedding night… and just five days into their marriage, her dear husband abandoned his loving wife and left to enlist in the army!

Fine! Be that way! She could pass her days perfectly well somehow, even if she had to do it alone!

Chu Lian put her household in order, charmed the rest of her new family, and did a little business on the side. She even opened up some new trade routes! Her days passed peacefully and leisurely… Until her dear husband got into trouble at the frontline of the war.

Hmph, isn’t he crawling back to me for help in the end? Forget it, I’ll go save him myself!

I don’t want to die. I want to be free. To that end, I shall….reconcile myself to the fate of becoming a “monster”.

A strange disease that racks one’s entire body with intense never-ending pain, until the person slowly withers away and eventually dies. After a few years of braving through the pain, the boy is in no luxury to even feel despair. With nary a soul to tend to him, he breathes his last.

The next time he opened his eyes, the boy had become an “Undead” of the lowest rank through the power of an evil Necromancer.

The boy rejoices at having his earnest desire fulfilled, which is a body that will never feel pain. However, he realizes that he is still under someone’s control and how it was no different from when he was cooped up in the hospital ward.

But the world would not leave alone the boy who only wished for peace.

The Necromancer who revives the boy from the dead, names him “End” and attempts to gain control over him.

The Undead Knights, lay their lives on the line to persistently chase after and annihilate the beings of the darkness.

With countless monsters under their command, the Demon Lords rule over their own lands while they all contend for ultimate supremacy.

The motivation being survival and freedom. The requirements being caution and power.

This is the tale of the cowardly King of the Undead. In his pursuit for freedom, he heads into battle and turns tail at times. He knows when to fear his opponents and when to waver in his decisions.

"Lu Lijun! what're you doing?"