MTL - Very Pure and Ambiguous: The Prequel - Chapter 6 I will help you cover the book cover.

One day, Luo Jian woke up from his sleep and found himself in a locked chamber where the door and window were all sealed. A note with a few lines written on it was tacked to the wall: “Escape from this room within an hour, otherwise, you will die.”

There is a sequel called Reincarnation Night (轮回之夜) that takes place in the same universe but has different main characters

- Description from Novelupdates

When a traverser mistakenly thought that he had crossed the back of Britain in the 1980s, and when he was suffering from childhood, he would eventually sink into the darkness in repentance, and a strange and familiar admission notice would light up his life.

But when he came into contact with the deeper darkness, did he choose to stay away from the abyss or jump into it without hesitation?

”You wait, I will be back soon.”

On the fifth floor of the St. Mungo Hospital, he finally firmly held her pale hand.

This is a story of biting teeth, even a liar that you can lie, and struggles repeatedly in pain and tenderness.

- Description from Novelupdates

When the human princess, Lareina is sent as a bride for a peace treaty between the demons and humans, she ends up in a political marriage with the second prince of demons, Prince Azrael. Lareina falls for his gentleness that sets him apart from the rest of the demons in her eyes but on the night of their wedding, he is deployed to the war.Years after his abrupt departure, Azrael has finally emerged victorious and returned. However, much to Lareina's dismay, he has brought back a beautiful demoness with him. At the receiving end of his hatred, a heartbroken Lareina tries to save their marriage until all her hopes are shattered. Determined to carve a way for herself, she decides to end the marriage but she is met with a new challenge when her seemingly uncaring husband suddenly refuses to let her go.

Dying at a young age after a disappointing life. Mat thought he hit the jackpot when he got reincarnated on a tropical island as a baby. Here, exploring mysterious lands and learning magic are a reality. The world of Elydes is beautiful and magical, wild and savage. While the Guide is impartial to all, people are not. Mat has the lowest starting point possible, and those like him rarely go far. To not let his humble birth define his life, he'll need to find the determination to grow stronger and delve into the mysteries of Elydes.