Global Reincarnation: Only I Know the Plot - Chapter 939:

The system: We must take the plot seriously!

Mo Fan: Ok.

The system: We cannot be OOC!

Mo Fan: Yes.

The system: We have to be cold. We must be ruthless. We cannot lose ourselves in this imaginary world.

Mo Fan: …no problem.

Not long after…

Mo Fan: System, can we talk? Hold my gong and take him away.

System: ……

- Description from Novelupdates

Returning to the Mysterious Era features a boy who can time-travel back to the past using old relics. The twist? He’s stuck in the body of the relic’s owner.After a near-death experience, Cassius unlocks his ability to travel to the past in the body of Li Wei, a member of the Wind Elephant Sect. Li Wei was a coward who lived a life of regrets up until the day the entire Wind Elephant Sect was mu*dered. As Cassius relives Li Wei’s past, he makes different decisions to show Li Wei a different kind of future.By living out the ups and downs of Li Wei’s life, Cassius is introduced to the world of Covert Martial Arts, ties that run closer than blood, and supernatural forces. Crossing the line between the ordinary and supernatural, he realizes there’s no way back. New friends and enemies slowly integrate into his reality.Now, he must uncover the secrets of Covert Martial Arts and get stronger to survive.

Nagasawa crossed to Naruto Universe and was bound to Konohagakure.

If Konoha is severely damaged and destroyed, Nagasawa’s lifespan will be reduced.

He panicked at the thought of the upcoming Nine-Tailed Demon Fox’s attack , and the thought of Konoha getting destroyed left him in despair.

Fortunately, while bound to Konoha, he can obtain templates of powerful characters.

At the beginning, He got the Whitebeard template! Since it’s the Whitebeard from the Summit War of Marineford, he can use Tremor-Tremor Fruit’s ability and Haki.

Facing the Tailed Beast Ball, which terrorized Konoha Shinobi, Nagasawa leaped and shattered the Tailed Beast Ball with one punch!

- Description from Novelupdates

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?