I Let You Take Charge of the Whitebeard Group Temporarily, and You Become the Fifteenth Emperor?

Luo Lan traveled through the pirate world, becoming captain of the Whitebeard Pirates' Squad Zero and activating a god-level manga system. He knew full well the fate of the Whitebeard Pirates at Marineford. So, he retreated to gain experience and improve his own strength. With the Battle of Marineford imminent, Whitebeard needed a period of intensive treatment due to health issues, so he temporarily appointed Luo Lan as acting captain of the Whitebeard Pirates. Months later, when Whitebeard completed his treatment, he was utterly stunned! Marco: "The Undying Flame is the true way to activate the Phoenix Flame!" Jozu: "Eighth Death Gate, open! Who can withstand my [Night Jozu] move?" Vista: "When I master the dual-sword style, my Zanpakutō, Nosei, that's when you prepare your final words!" Little Oz: "The super-multiplication technique in Butterfly Transformation Mode is so fascinating!" ... Whitebeard: "I asked you to temporarily take charge of our group, and you've actually raised the captains' strength to that of a general?!!"