Naruto: The Wind Calamity - Chapter 641 - 635 : Earning Respect

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates

Arthur was a weak and cowardly boy who lacked the power to protect anyone—a truth brutally demonstrated when his parents were massacred while defending him during a Gate outbreak. As the sole survivor, Arthur spent weeks believing his life was over. When intense chest pains began, he assumed he'd been infected with corruption by the void creature that killed his parents and was merely waiting for death.What Arthur didn't expect was that these sensations actually signaled his Realm Core forming. In two months' time, he would be forcefully transported to the next realm and awaken new powers, becoming one of the world-renowned “Chosen” who protect humanity from Gate outbreaks. Now Arthur must rise through the heights of power, climbing each of the seven realms in hopes of saving his world... or does he?

When Zhou Shu woke up, he learned that he had become a Forging Apprentice at a workshop in the Forging Division of the Great Xia empire.

“I hate this world. I hate everyone. There's no justice for the weak,”Once happy and carefree, Reign's life took a dark turn when he was kidnapped and undergone brutal experiments.These trials broke not only his physical body but also shattered his mind.In the end, his body couldn't withstand the ordeal, and he died like a pitiful lab rat.But death wasn't the end.He woke up in a new world as a corpse, armed with the Ultimate Mutation System.A system that enabled him to mutate and gain power in exchange for his own humanity.Determined to avoid being exploited again, he sets out to become a true powerhouse.He knew that being weak would only make him a target, especially now that he was a monster.“Kill or be killed.”That was his only option.