MTL - The Reader and Protagonist Definitely Have to Be in True Love - ~ 79, Jinjiang starting

Xuanyuan was reborn into a strange new world where training to be a Xian was a cornerstone. There was however something ancient dwelling inside his body. He could now devour all of creation…

Su Shuilian was the first legitimate daughter of a renowned embroidery family, but she was murdered by her jealous family member. After death, Su Shuilian’s soul enters an unknown female body who lives in a dynasty she had never heard of.

While trapped in the wilderness with her wolf pup companions, Shuilian picks up an assassin who was betrayed by his organization and saves him from the brink of death.

After making it out of the dangerous forest, the two travel to a small town with few inhabitants. There, they find a location with a picturesque scenery and disguise themselves as a married couple to buy a house to settle down in.

She was a girl unfamiliar to this world, and he was an infamous assassin. Journey with them as they adapt to their new life…

- Description from Novelupdates

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.

You are the ruler, I am a subject, you want loyalty, I’ll give you loyalty. You are the ruler, I am the subject, you want my sacrifice, I will sacrifice for you. This lifetime, we’ll only be ruler and subject…… cannot become the one who accompanies you to experience everything.

A deposed empress, a failure of a substitute. Charging into battle, he was the emperor, and she, his general. But within the intimacy of their military tent, he was her husband, and she, his wife.

But everything was star-crossed. For the one he loved the most, he would push her into hell again and again.

- Description from Novelupdates