Vinsmoke Sanji, third son of the Germa Kingdom's royal family, endured a traumatic childhood under his father Judge's genetic modification experiments. While siblings Ichiji, Niji, Yonji, and Reiju gained superhuman abilities and suppressed emotions, Sanji remained human due to his mother Sora ingesting a drug to preserve his humanity, sacrificing her health. This led to severe abuse from his brothers and rejection by Judge, who imprisoned him and staged his death. Sanji escaped with sister Reiju's aid, fleeing to the East Blue. After working as a cook on the cruise ship Orbit, Sanji encountered pirate "Red Leg" Zeff during an attack. Stranded together on a rock with scarce food, Zeff gave Sanji all rations and ate his own leg to survive, instilling Sanji's lifelong principle to never refuse anyone food. He trained under Zeff at the Baratie restaurant for nine years, mastering cooking and developing the kick-based Black Leg style to protect his hands. He adopted an unwavering chivalry code, refusing to harm women under any circumstances. Sanji joined the Straw Hat Pirates when Luffy defended the Baratie from Don Krieg. His dream is to find the legendary All Blue sea, merging fish from all oceans. As the crew's cook, he provides vital sustenance and tactical ingenuity, executing covert operations like disabling Enel's ark in Skypiea or closing the Gates of Justice at Enies Lobby. His perceptiveness shines in strategies such as impersonating Mr. 3 to deceive Crocodile. Sanji's past resurged in the Whole Cake Island arc when his family forced his marriage to Charlotte Pudding to ally with Big Mom. Despite initial reluctance, his compassion toward Pudding catalyzed her betrayal of Big Mom. After Luffy's intervention, Sanji reconciled his identity, accepting his Vinsmoke lineage while rejecting its values. This awakened latent genetic enhancements—boosting durability, speed, and regeneration—though he destroyed his Raid Suit to sever Germa ties. His eyebrows' spiral direction temporarily reverses during power activation, symbolizing this transformation. In combat, Sanji exclusively uses kicks, evolving his Black Leg Style with techniques like Diable Jambe (fire generation through friction) and Ifrit Jambe (blue-flame kicks amplified by Armament Haki and his exoskeleton). He wields advanced Observation Haki for movement prediction and Armament Haki for defense. Post-timeskip training in Kamabakka Kingdom refined his abilities, adding Sky Walk aerial mobility and Attack Cuisine recipes enhancing physical resilience. Sanji balances composure with extreme reactions to women or crewmate provocations, especially his rivalry with Zoro. Despite self-proclaimed romanticism, he prioritizes crew safety over personal desires, as when refusing Pudding's marriage to protect the Straw Hats. His bounty rose from 77,000,000 to 1,032,000,000 berries after key conflicts, though authorities consistently underestimate him.