System: There's Something Wrong With My System. - Chapter 8 - The History of Mana

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

Humans, once the masters of Earth, were losing their place to the inexplicable phenomena known as Objects.And this is a story about becoming an Object and living worry-free in the Seoul of such a world.

As soon as Qin Feng opened his eyes, he was horrified to find himself lying in a drafty thatched hut. The problem was that he was still in his villa! What was even more horrifying was that there was another man lying under the blanket next to his legs!

“You, you, who are you?”

The man quietly sat up, exposing his upper body. He looked at him fixedly for a moment, then took a broken bowl from the table by the bed. He said in a muffled voice, “Wife, drink this water.”

Qin Feng rolled his eyes and fainted. Without permission, it is forbidden to reproduce or adapt it. Violators must be investigated.

“Impossible… Why are you not following my orders!? Clearly I sucked your blood, why!?”

On the very first day of high school, the youth subscribing to the philosophy of “absolutely ordinary everyday life,” Kujou Hisui, encountered disaster head on: He was attacked by Rushella Daamu Draculea, the vampire who had lost her memory. Rushella was greatly intrigued to find her vampire powers ineffective against Hisui. Not only did she make Hisui’s home her own, she even enrolled in his school to stick to him–

Hisui had no choice but to help Rushella regain her memory. But before one crisis could be resolved, many more had risen. With tempting advances from the mysterious Sudou Mei, and kidnapped by the girl from the Supernatural Investigations Section in search of Rushella, Hisui’s ordinary life has been replaced by its complete opposite, drama–

Romantic comedy and supernatural action in a school setting!