Mushoku Tensei Jump

From the introduction: After the ancient Dragon God waged a titanic war and the seven original worlds crashed into one another, and after the millennia of racial war that followed, the world you find yourself in resembles much in the way of the aesthetic ideal of a fantasy world. Here you will find sword and sorcery, men and demons, and adventure and intrigue. But under the familiar veneer lays a world that possesses its own unique appeal.