Dragoon - Extra: Mystith is Working Hard

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

Year 2022, December the 1st. This was the day it all began.

Labyrinths had started forming all around the world, hundreds and thousands of people lost their lives as casualties.

Mutations followed after, occurring amongst the people, they began awakening super powers, the same for animals.

However these mutations brought along a virus. It quickly spread amongst the dead as they began to rise. Humanity had begun its fall.

Gray who had given up all hopes of living life, was granted a system with a special ability. On the very same day, of the outbreak, he was consumed by a labyrinth.

By the time he had gotten out, a week had passed. It was hell all around. A virus had broken out from the mutations, the dead were walking and spreading this virus.

However this was only the beginning.

Over time the mutations began to evolve and people learnt that the through the cultivation of their powers, they could improve their abilities.

[Post-apocalyptic + No romantic pairings + Overpowered system + Management + Please read the bottom of the synopsis + Initially low-priced, enter at your own discretion]Gu Wanyin never imagined that not only would she transmigrate, but she’d end up in a post-apocalyptic world! Opening her eyes to find herself surrounded by zombies with only two pitifully thin adorable children by her side, Gu Wanyin thought: This is the end of me!System: Impossible, absolutely impossible!After binding to the most powerful hotel system in the post-apocalyptic world, Gu Wanyin embarked on a delightful journey of raising children and managing a hotel. As the hotel’s guests increased, so did her rewards! But could someone explain to her why a hotel that unlocked noodle shops, hot pot restaurants, and buffets was understandable, but why did it also have KTV, movie theaters, libraries, amusement parks, hot springs, schools, and hospitals? And even a zombie-killing simulation training camp? Wait, there’s even more…It seems she’s destined to transform this hotel into the only paradise in the post-apocalyptic world!

All Things of this World, Turn to Ashes, Flowing Blade-like Flame!

Crossing over to the world of pirates(the one piece world) , in the era of pirates, the Roja from eleven years ago obtained a Sword Soul system that lets him strengthen infinitely and extract various kinds of skills.

Flowing Blade-like Flame (Ryūjin Jakka) , Mirror Flower, Water Moon (Kyoka Suigetsu), Moon Fang Heaven-Piercer (Getsuga Tensho), Thousand Cherry Blossoms (Senbonzakura)……

“If this sword descend, you may be roasted to death.” Roja looked at Akainu in front of him and seriously said.

- Description from novelupdates