Prologue:
It’s been 2 years since Monkey D. Luffy entered the Grand Line. They've defeated villain after villain, discovering new and wonderful places, and gaining new companions and friends along the way.
After crossing the Red Line by the underwater passageway of Fishman Island, the Thousand Sunny emerged on the other side. They had officially entered the New World. It wasn’t long until the Mugiwara’s were truly recognized as a threat by the World Government. However, the Government wasn’t going to get involved just yet. They would wait and let the Emperors of the New World to take them out.
Kaidou, the same man who had defeated Gecko Moria a few years back, was aware of the Mugiwara’s existence and particularly curious as to how such a small pirate crew had grown so enormously dangerous in such as short amount of time. This was terrible luck for the Mugiwara’s since it just so happened Kaidou was an Emperor, one on the same level as Whitebeard himself.
Almost effortlessly, through brute strength alone, Kaidou took out every since Mugiwara, from Brook to Luffy. Kaidou wondered how such pathetic pirates had made it so big. He quickly discarded the though, putting it away that they had just gotten lucky, or the world outside the New World had grown weaker in the past years.
Kaidou, feeling the same sympathy that he had for Moria, decided to let the pirates live. However, he did send them on their way toward the Government, who quickly captured the pirates and sent them straight toward the infamous pirate hell, Impel Down.