One Piece: I am Imu - Chapter 296: A Duel of Magic and Steel

Noir, third son of a “beggar noble,” lost his job and was at a loss, but fortune struck just as he was contemplating becoming an adventurer.

A small immortal clan, with the efforts of the ancestors of the past dynasties, slowly developed into an immortal clan. This is the history of the development and growth of a small family. During this period, there were ups and downs, and there were also struggles for power and profit.

- Description from novelbuddy

Humanity has been gradually transported to the Abyss by a bored god to compete against other races and monsters.The problem is… humanity failed. In a last desperate push the strongest survivors chose a comrade to travel as far as possible back in time.

I was a good looking prince when I was reborn, and because I could do indecent things as much as I like, I decided to make a harem while traveling with a beautiful female elf~