The Duke's Passion - Chapter 869 That’s rude

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

Leon Walker, the world-weary genius of modern world, is killed in a freak accident — the notorious Truck-Kun makes an appearance. Death is only the start. He finds himself reborn in a new world, Galvia, reincarnated into the strong but failing body of Duke Leon Moonwalker, one of the only three Grand Dukes of the Moonstone Kingdom, a minor but strategically powerful kingdom within Galvia. As Leon attempts to understand his new world, a strange voice resonates in his head. “Supreme Spouse System Activated.”.

A man who was once called the world strongest agent ended up becoming a teacher after his retirement to train the new generation of agents. After many years of training his disciples, he is killed at the age of 60 by the ploy of a secret organization and was reincarnated in another world with all his past memories.Though he was surprised by the magic and the strange species of that world, he adapted very fast to his condition as a newborn and took advantage of it. He acquired special magic and gained a massive amount of strength thanks to his tight discipline in order to reach his goal: resume his career as a teacher which he left halfway through in his previous life.This is the story of a man who based on the memories and the experiences of his previous life, became a teacher who travels through the world with his new students.

A mysterious natural phenomenon caused the Earth to be plunged into darkness. The world turned into an endless bloody chaos and mankind is on the brink of extinction…