I Shall Seal the Heavens - Chapter 6: The Delights of the Copper Mirror

Zheng Tan somehow returns to the year 2003, turning into a black cat. Picked up from a rubbish heap by the Jiao family, he is given the name “Charcoal”, and so begins the life inside Professor Jiao’s family. Zheng Tan remembers that he was once a person, but currently his body is that of a cat. He has no way of speaking the human language, but can understand it, and even retains the thinking and IQ of a young 20 year old youth. Read along as he adapts to this new world, and somehow tumbles from a group brawl to catching a thief.

- Description from Novelupdates

Kim Jeongjin, an editor of a publishing company on the brink of closing due to bankruptcy, ends up transmigrating inside a fantasy novel as the incompetent youngest son of a wealthy family.

And here he thought that he should live a rich life in this life…

“Why was I given a high-level skill? Don’t even bother!”

Ron finds himself reborn in the world of One Piece, stranded on a remote island in the East Blue. But he's not just any ordinary child—he’s bonded to a mysterious sign-in system that grants him powers with every new location he visits.At his first sign-in, he unlocks the legendary Sun Breathing Technique, along with a boost to his vitality. From Shitmotsuki Village to Skypiea, Enies Lobby to Marineford, Ron travels the world, collecting extraordinary rewards that make him a force to be reckoned with. The Raikiri, one of the 21 Great Grade Swords, Armament Haki, Observation Haki, and more fall into his hands.As Ron steps onto the battlefield of Marineford during the legendary Summit War, the mightiest warriors—Four Emperors and Marine Admirals alike—pause, stunned by his presence. But Ron merely waves them off, “Don’t mind me. I’m just passing through.”Join Ron on his journey across the Grand Line as he signs in at iconic locations, growing stronger with every step. This is not just an adventure—it’s a legend in the making.

Forty years ago, demons invaded the eastern continent. Coming from another realm, they hunted the humans, and people soon began to wage war with them. Before long, there were those among the humans who inherited the demons' abilities.Demon hunters are currently the most in-demand profession. Although the chance of dying during a raid was high, the hunters were mostly popular among the common people. If you have some demon blood in your body, then the path to the Hunter's Association is open to you.Year 2066, Seoul. The territory of the former city is divided into three parts. Green Zone, Orange Zone and Red Dangerous Zone. Although mostly ordinary people and workers lived in the green zone, there was a chance for demons to get into it. That's why demon hunters patrol the whole area, sacrificing themselves for the lives of people.The main character, Lee Ki-hyun, inherited 50% demon blood and became the world's first SSS-ranked demon hunter. He will have to go through the path of a demon and learn the truth about his parents to save humanity.