It's Been 20 Years Since I Signed in to Impel Down, and I Knocked Out Akainu with One Punch

Traveling through the world of One Piece, he was arrested and entered Impel Down City. Fortunately, the god-level sign-in system was activated. "Ding dong, you signed in successfully and obtained the Sun Breathing Technique!" "Ding dong, you signed in successfully and got your Zanpakutō!" "Ding dong, you signed in successfully and got March of the Dead·Eight Rooms!" "..." After signing for twenty years and knocking out General Akainu with one punch, Jiang Xuan found that he seemed to be invincible! This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.