One Piece: Supreme Check-In System - Chapter 37: Arrival in Fish-Man Island

There was a man in the modern world that built his business empire from scratch. He was hailed as a genius by his peers and was respected worldwide due to his contributions to the world.If it is not only for that unfortunate accident that led to his death. He was a man who could potentially change the world with his mind that still stores a plethora of ideas.But—fate had others plan with him. He found himself in another world, what’s more, it’s primitive and technologically backwards compared to his last world. And what’s more, he turned into his younger self, and in this world, he was an orphaned boy.For him to survive, he must use everything that he had at his disposal, and that was all in his head.

Uchiha Kai has been cautious since he came to this world. He vowed that he must be cautious and go to the end.

But one day he received a mission – to cover the wave wind team to blow up the Kamabashi Bridge, Uchiha Kai knew that he was going to be unlucky…

- Description from novelbuddy

Cain was an ordinary boy who loved creative works, especially when it involved anime and games. Suddenly, he found himself in a strange space with an extraterrestrial creature, a cosmic horror called Bishop that he couldn’t explain in words besides scary.Given the authority of a King, he was tasked to create dungeons in the multiverse in order to change his future. He had been turned into the Dungeon Maker. The more known his dungeon was, the stronger he became!Rias: What are you? A Devil?Dante: Now, now. What are you? Wow, I drank too much. Look at her, a sexy devil.Zoro: Where am I? Is that a sea monster? Good, I will bring meat for Luffy.Helldiver: For Democracy!!!All worlds became connected due to the dungeon. However, don’t worry!Everything was under his control.

A 13-year-old deaf teenager living in the 21st century suddenly found himself as a young boy in Japan during the early 1900s. With two World Wars, two nuclear bombs, Hitler and many other disasters awaiting his future, he thought things couldn't get worse.Except it did.He found out later on that he had actually reincarnated into the world of Demon Slayer where man-eating demons ruled the night. He thought things couldn't get worse.Except it did.But hey! At least he had unparalleled talent, incredibly special eyes and future knowledge.How will the story of Demon Slayer change with the addition of this unique character? Will so many still die if the Hashiras had one more pillar in the final battle?Or will the story end on a much happier note?