Sett, the ruler of Ionia's underground fighting pits, accidentally fell into the world of pirates after a battle.
No Devil Fruit, no System, no golden finger. All he had was the steel-hard body granted by his Vastaya blood and the instincts honed over ten years in the fighting pits: the thrill of battle. The more damage he took, the harder his counterpunches hit.
Starting from a rundown fighting pit on Mox Island, he recruits Iron Fang, crushes the Poison Scorpions, fights the Marines, and charges into the New World. The golden fist flag of the Fist Gang spreads across the seas. The Shichibukai, the Four Emperors, and Marine Headquarters all have to play by his rules.
“On these seas, I'm the one who calls the shots.”
(No Imu. They're too overpowered, I don't know how to fight them.)