One Piece: Unreal Adventure - Chapter 27: No More Plateau

This is the story of a young man who was reincarnated as a dragon with a near-insatiable curiosity. Initially sparked by questioning his own reincarnation, he quickly gets lost in the endless world of magic, using his deep understanding of advanced sciences to learn the laws and properties of a new type of energy known as mana.However, soon enough, the table would flip, and he would begin using that very same energy to expand his knowledge of science, to the point that he would begin questioning his own understanding of the world.Although not his original intention, with the combination of his intelligence, expanding curiosity, and the 'miracles' that occurred to allow for his existence, he quickly found himself climbing the mountain of strength as if it were a small hill before eventually climbing to a point where it seemed as if he himself was the peak itself.Even if.. that was never the case...There is mild gore, and profanity is 'censored' toward the beginning, but not later in the story.

Rise of the Arms Dealer in the World War tells the story of a man from the modern world, thrown back in time to a pivotal moment in history. Armed with knowledge of advanced weaponry and the sharp instincts of a seasoned weapons dealer, he wastes no time in exploiting the chaos of historical wars and political upheavals.Building an empire not just in arms but across industries, he crafts vehicles, machinery, and technology far beyond the reach of his time. With each calculated move, his influence spreads like wildfire, positioning him to control the tides of conflict.After World War I, he seizes the opportunity to buy up factories and cutting-edge technologies from the defeated nations, biding his time to prepare for the next global war. His eyes are set on World War II, where he plans to sell weapons on an unprecedented scale, shaping the course of history.A villain at heart, he is cold, calculating, and without a shred of principle. He deals to whoever bids the most, indifferent to the consequences. As his empire grows, so does the power he wields, but with it comes a relentless struggle to keep the forces he's unleashed in check.

A man who was once called the world’s strongest agent ended up becoming a teacher after his retirement, to train a new generation of agents. After many years of training his disciples, he was killed at the age of 60 by a secret organization’s ruse and was reincarnated in another world with his memories intact. Though he was surprised by the existence of magic and the strange species in that world, he quickly adapted 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 rigorous 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 students.

[I was reincarnated as an F-class Hunter.

…it’s a problem because they don’t treat me that way.]