Kikaku Hazure no Eiyuu ni Sodaterareta, Joushiki Hazure no Mahou Kenshi

After sacrificing his life in a tragic accident to protect a young girl, a young man finds himself reborn in an unfamiliar world. Alone and vulnerable in this new reality, he is eventually taken in by an elderly man who offers him shelter and guidance. However, his savior is far from an ordinary elder. The old man is, in fact, a legendary hero—one whose overwhelming power has left him completely detached from the basic common sense of everyday life. Raised under the tutelage of this eccentric and extraordinarily powerful figure, the boy undergoes rigorous training that defies all conventional logic. As he matures, the unconventional teachings mold him into a magic swordsman whose abilities are just as unorthodox as those of his mentor. Equipped with skills that shatter the boundaries of what is considered normal in this world, he steps out to forge his own path. With extraordinary strength and a perspective shaped entirely by a hero who knows nothing of societal norms, his remarkable journey through this new world quickly leads to unexpected encounters, drawing a growing circle of companions—and an ever-expanding harem—into his extraordinary life.