One Piece: Fist of the World - Chapter 18: Art is an Explosion

I got transmigrated into a game I’ve never seen before.

I thought it was a top-notch RPG and spent 30 years on it.

I retired as a war hero and planned to spend my remaining time leisurely.

But it turns out, it was an academy story?

Fifty years ago, the oxygen in the atmosphere changed, giving rise to a new form of air known as Spiritual Qi. Humans, plants, and animals alike suddenly awakened latent mutant genes and began evolving, gaining Superpowered Talents and Classes. Life took a new turn, and humanity had to adapt.Everything seemed to be going well until, fifty years later, a 16-year-old boy named Klaus awakened a terrifying Talent and Class. His awakening marked the beginning of a new era in human evolution.Unbeknownst to everyone, Klaus, who was shunned by society and dropped out of school to work for a better life for himself and his mother, was actually the last of the Nine Paragons—a being so powerful that even the heavens feared him.Watch as Klaus climbs the ladder of strength, pursuing absolute power with a single purpose: to protect and make his mother happy.

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.

Protagonist travels between different anime worlds to right wrongs and uncover his reason for being along the way.

- Description from Novelupdates