Lu En awakens in the dangerous world of One Piece as the grandson of the Marine Hero Monkey D. Garp and the son of the Revolutionary Army leader, Monkey D. Dragon.

With a carefree younger brother named Luffy on the horizon, Lu En knows he must become strong to survive the treacherous seas. Fortunately, he possesses a unique cheat: the Ghost Back System. This system rewards his grueling physical training with exponential stat boosts, turning his 'devil training' into a path of rapid godhood.

Starting with a mere tenfold cultivation multiplier, Lu En pushes his body to the limit, unlocking the legendary 'Ghost Back' physique. As his completion rate climbs to 10%, his training efficiency skyrockets to a hundred times that of ordinary men. Now, a three-year-old boy with the muscle definition of a veteran warrior, Lu En is determined to master all three types of Haki before his fourth birthday, aiming to surpass even his formidable grandfather and reshape the fate of the world.