Betrayed, I Met The Demon Lord - Chapter 48 – The Way of The Sandler

When I cleared the final chapter of a game that was a national failure, I became an unnamed side character in it.

A non-standard, unmeasurable, EX rank supporting character.

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

On an ordinary day, Lucius stumbled upon a strange, run-down shop. At first, he assumed it was abandoned—until he stepped inside.[You have entered the Universal Alchemy Store.][Congratulations! You are now the store’s owner.][Please craft your first potion.]Lucius blinked. 'What kind of joke is this?' But as if guided by an unseen force, he followed the instructions. Minutes later, his first creation was complete.[Love Potion: The drinker will fall in love with the first person they lay eyes on.]Lucius swallowed hard. 'Wait… does this actually work?'Before he could process it, the shop’s door swung open.Standing in the entrance was no ordinary customer—she was an elf. Long, pointed ears, mesmerizing green eyes, and a body sculpted by the gods. A visitor from another world.A dangerous thought crept into his mind.'Should I test it on her?'

Luo Yi had secretly loved Chu Chen for quite a while and discovered that Chu Chen seemed to really like. . .

Um. . . really like certain 18+ things. . .

So Luo Yi decided to follow Chu Chen’s lead and walked onto a path of being f*cked. . .

- Description from Novelupdates