The Wrong Way to a Demon Sect Leader - Chapter 61

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

A man who was once called the world’s strongest agent ended up becoming a teacher after his retirement, to train a new generation of agents. After many years of training his disciples, he was killed at the age of 60 by a secret organization’s ruse and was reincarnated in another world with his memories intact. Though he was surprised by the existence of magic and the strange species in that world, he quickly adapted to his condition as a newborn and took advantage of it. He acquired special magic and gained a massive amount of strength thanks to his rigorous discipline, in order to reach his goal: Resume his career as a teacher which he left halfway through in his previous life. This is the story of a man, who, based on the memories and the experiences of his previous life, became a teacher who travels through the world with his students.

My younger brother died.And it happened inside the prestigious private school that I struggled so hard to get him into.As I was crying in despair in front of his grave,A strange man who claimed to be the student council president appeared and made an unbelievable offer.“Would you like to go back one year if you could?”He seemed like a swindler, but faced with sudden despair, I had no other choice.I grasped at this rotten lifeline and hastily made a deal with him.And surprisingly, I really did go back one year in time.Without wasting time, I immediately transferred to that problematic private school. To protect my younger brother who was still alive.But this school, the atmosphere is not right.Ghosts and spirits appear all over the school, and ‘ghost stories’ occur.Somehow, my brother seems to be connected to these strange phenomena.Will I, Melody Hastings, be able to safely solve the ghost story, protect my younger brother, and get out of this school?

The young lord of a small and weak country saves a dragon beside the sea one day.