Who Let Him Play Yu-Gi-Oh! - Chapter 187: A Little Swap

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates

An innocent boy from Earth who was sheltered all his life finds himself reincarnated into a world full of magic, a world as beautiful as it is horrifying. Fate brings him together with his new loving mother and sister, and they face the trials together as a family. Follow their incredible story as they struggle to survive and create a better life for themselves.

It is the turn of the century and humanity has ignorantly stepped into the starry space to lay themselves bare under the eyes of gods. The young man Luo Nan bears the sins of his forefathers. He walks out of a laboratory and is seen holding burning notes up high, his feet treading on the bones of gods. A myriad of living beings are formatted in writing. Universes are added and deleted in the star records.

How long will it take for a murdered thief to distill into something monstrous? In this story the darkness only grows stronger, and its reach only grows wider as it expands by devouring the life that surrounds it. This is a dark fantasy where evil is a where, not just a who that focuses on slow progression, undeath, and atmospheric storytelling.