Luck Lock Franzen

An S-rank adventurer who told his teammates to leave him behind after monsters attack in a dungeon. He comes back ten years later, now younger, having beat all the monsters in the cave. Upon his return, he discovers he was made a hero and has had a statue erected of himself in the middle of the royal capital.

He meets up with his old friends, deciding to start over again, as an F-rank Adventurer, named Lock. He joins up with two other F-rank adventures, one a fireball caster, Ario, and an archer, Genie. Along the way he also meets a B-rank Adventurer, Shia.

(Source: Wiki)