Mark of the Fool - Chapter 12: The Traveller’s Magic

In the rebirth, in order to prevent the tragedy of the previous life from happening, Bai Yu decided to rush to the [Tower of God] at any cost, and face everything together with his sister!

However, Bai Yu, who was bound by the system, mutated his bloodline, and transformed into a black-scaled python seems to be developing on a completely different path from his previous life…

- Description from novelbuddy

It tells a poignant love story. He was the most heroic man in history, and before his death he sang a sad song about a woman; she was the most charming woman in history, and before her death she danced a story about steadfast love. The story of the two had no beginning, only an ending of parting in death. After his death, he became a demon for her, and fought fiercely with the immortals of the three realms. After he was killed, his unique seven souls were hidden in various places by the immortals; she became a ghost for him, and before she passed away, she smashed Meng Po's soup bowl, and her soul flew away. Even so, he still vowed to subvert the three realms, find her in the next reincarnation, and marry her, even if it took a thousand years.

She, a modern hidden ghost leader of an organization which gathered insane prodigies proficient in the various differing skill-sets. Highly skilled in medicine and poison, executes covert assassinations, viewed as insane and demonic in the eyes of people of the world. Killed in an accident, and reborn into the body of a disfigured young girl.

What? Face disfigured, identity stolen? A return to the family dim and hopeless? Her identity can be given up, her family can be forgone, but as for the one who harmed her predecessor who inhabited this same body, if she didn’t at least make them scream in unimaginable agony and throw them into a state of wretchedness, how could she live up to her demonic reputation? Endless turmoil ensues and it’s a battle to dominate over all! See how she shook the world dressed in a suit of red, her sword up against the dominant powers that rocked the Heavens! Her name spread across the seas, shocking the earth!

- Description from Novelupdates

I was betrayed in my first life.A cripple, broken and discarded—I died after catching the one I loved in bed with the only person I ever called a friend.That was the start of real torment.When I woke up, it was in another world.A goddess stood before me.She told me I could go back.Back to my world.Back to everything I lost.All I had to do… was play my part.The side character.And I did.I followed the script.Played my role to perfection.They hated me.Mocked me.Used me.Again and again.But I kept going. Because I believed her.Because I wanted to go home.Then one day, I found out.The hard way.It was all a lie.There was no going back.There never was.She used me.Again.Just like everyone else.Thrown away like trash once I outlived my usefulness.That was the day something inside me snapped.And so, I made a vow.I would take everything from her.I would enslave every single heroine she chose.And I would kill the hero she placed all her hopes on.If she wanted to protect this world…Then I would burn it down.But the more I tried, the more things started to change.And then one day—I found one of the heroines.One of the hero's yanderes I had enslaved.She stood there, trembling, a knife in her hand.“You’re not going anywhere,” she whispered, eyes wild.“I won’t let them have you. You belong to me.”...What. The. Fuck. Is. Happening?!