Immortality: My cultivation Has No Bottleneck - Chapter 653 - 238: Liang Sheng Controls the Six-Tailed Demon Sovereign, Unraveling the Secrets of the Underground Demon Clan (Seeking Monthly Votes!)

Surgeon Guan Ryo Is reborn in Naruto’s world! Enjoy his trip as he uses his knowledge of the story to find his path in this troubled world and eventually stand at the top of Konoha!

- Description from Novelupdates

In a world shadowed by death, the silent realms await, home to the undead and the Grim Reaper's sanctuary. As long as death's presence endures, the great Undead Queen will return.

…but it seems pretty doable.

Depth-Dwellers are long extinct.All except for a single one..Waking up after being dragged by the pressuring tides, Cetas finds himself in the middle of an unfamiliar ship, greeted by a distinct group of pirates.Without any knowledge about humanity at all, he traverses the seas with the unknown band of pirates and learns about their culture and speech. In a world where 'Zeal' serves an essence for humanity's power, Cetas must learn to ascend the ranks to protect those that he cherishes.For when the mysteries beyond the fog arises, the Dreadspawns begin to wreak havoc, and the Leviathans rise up into the world..'Would Cetas become a 'human' worthy of saving those that he loves?'