Marineford World Government ke Navy Headquarters ka markaz tha. Ye ek bara sa island hai jo Grand Line mein Paradise ke area mein tha. Marineford arc One Piece ka sab se emotional aur heartbreaking arc maana jaata hai. Yahan "Summit War" hui — Whitebeard Pirates aur unke allies vs. Marine Forces aur Shichibukai. War ki wajah thi Portgas D. Ace ka execution — jo Luffy ka adopted bhai aur Whitebeard ka commander tha. Whitebeard Edward Newgate, duniya ka sab se taqatwar aadmi (us waqt), apni poori fleet ke saath Marineford pahuncha. Whitebeard ne apni Gura Gura no Mi (Tremor-Tremor Fruit) powers use ki aur poori Marineford ki dharti ko hila diya. Luffy bhi Impel Down se bhaag kar Marineford pohancha. Ace ko bachane ki koshish mein kaafi qareeb tak aaya lekin aakhir mein Admiral Akainu ne Ace ko maar dala. Ace Luffy ki baahon mein dam toad gaya. Uske baad Whitebeard ne bhi apni zindagi qurban kar di — apne bachchon (crew) ko safe nikalne ke liye. Whitebeard ne jaate jaate kaha — "The One Piece is real!" — jisne duniya mein ek naya daur shuru kar diya. Marineford ke baad Navy ne HQ nayi jagah move kar diya aur Akainu naya Fleet Admiral ban gaya.