One Piece: The Strongest Swordsman - Chapter 40: Aftermath (2)

A legendary powerhouse of his generation, tired of the bustle of the peak, returned to the ordinary city and started a new life as an ordinary teacher. He wrote the legend in the city.

Magnificent mountains and rivers, the rising powerful ones. Some ancient martial art masters stood at the peak, becoming legendary. Some financial crocodiles rose up in the minuscule places, laughing arrogantly.

However, watching the school beauties was better than fighting and killing; educating was better than fighting for fame.

- Description from Novelupdates

He kept her by his side, never letting go! “Please, can you let me go?” “Impossible,” he said, “unless you're no longer my only one.” After they fell in love, he declared possessively, “I want to keep you by my side, to make you belong only to me. You can only love me too, your mind, your world, must be filled with only me.” Yet his domineering love sent a chill through her.

A world where people awakened abilities called Skills to those who come of age. The protagonist, Awakened with three godly cheat skills, does he uses them and rise to an existence called a hero or becomes a person who only cares about his own life.